A U.S. military strike in Iran reportedly killed more than 168 civilians, most of them young girls, at the Shajareh Tayyebeh school in the city of Minab on Feb. 28. It was one of many reported incidents of civilian harm from U.S. and Israeli operations in the country. Initial U.S. military inquiries reportedly confirmed U.S. responsibility, making the devastating incident the largest civilian death toll of any single U.S. attack since 1991. Any military operation that results in such an outsized civilian death toll must be met with a credible and thorough investigation, followed by appropriate accountability, including measures to hold individuals responsible where merited.
Members of Congress and human rights organizations have called for a formal investigation into the strike, including to determine whether war crimes were committed. On March 13, Secretary of Defense Pete Hegseth told journalists in a press conference that U.S. Central Command (CENTCOM) had designated an investigating officer to complete a command investigation into the strike. The investigation in question is often known as an “AR 15-6” investigation, an administrative investigation named for the corresponding Army regulation. (It is worth noting that the United Nations Fact Finding Mission on Iran is also investigating the incident, as a priority, and those experts initially found Iran’s reported casualty numbers credible.)
The inquiry into the Minab school strike is not the only ongoing AR 15-6 investigation into civilian harm. According to an exchange between U.S. Southern Command (SOUTHCOM) Commander General Francis Donovan and Representative Sara Jacobs (D-CA) at a recent House Armed Services Committee hearing, SOUTHCOM currently has two 15-6 investigations underway related to civilian harm from Operation Absolute Resolve in Venezuela. With active U.S. military operations in Iran, in the Caribbean Sea and Pacific Ocean, in Ecuador, and in Somalia, as well as recent operations in Venezuela, Iraq, Nigeria, Yemen, and Syria, other undisclosed 15-6 investigations may be ongoing as well.
Both of us have extensively studied patterns and practice of U.S. military investigations, including through a two-year study conducted by the Center for Civilians in Conflict (CIVIC, where one of us, Annie, works) and Columbia Law School Human Rights Institute (where Priyanka worked previously). The study, issued in February 2020, reviewed more than 200 15-6 investigations into civilian harm released by CENTCOM as a result of requests under the Freedom of Information Act (FOIA). Our research identified numerous patterns, shortcomings, and recommendations for improvement.
Thorough and credible military investigations are essential for a range of purposes: to comply with international humanitarian law (IHL), or the law of armed conflict; to allow for appropriate acknowledgement and redress for civilian victims and their loved ones; to avoid preventable future civilian harm by correcting practices that lead to error; to protect broader foreign policy goals; to ensure military discipline and professionalism; and to protect or restore public confidence. Governments have a duty under IHL to investigate possible IHL violations, including apparent war crimes.
Below we outline key aspects of a typical 15-6 investigation, as well as what a credible inquiry into civilian harm must entail.
Background: U.S. Civilian Harm Reviews, Assessments, and Investigations
Not all civilian harm reports result in administrative investigations. According to the DoD Instruction on Civilian Harm Mitigation and Response (CHMR DOD-I), all reports of civilian harm begin with an initial review to confirm whether there was a U.S. operation in the same general time and location as the civilian harm report and deconflict the report with possible duplicates. Reports that pass an initial review move to a civilian harm assessment, which aims to identify whether it is “more likely than not” that civilian casualties or damage to or destruction of civilian objects resulted from U.S. military operations.
Many civilian harm inquiries are concluded at the assessment stage, with the determination of whether civilian harm more likely than not occurred as a result of U.S. action. Some civilian harm incidents are referred to a command-directed administrative investigation conducted in accordance with military regulations (Army Regulation 15-6, or where applicable, Navy Judge Advocate General Instruction 5800.7G or Department of the Air Force Manual 1-101). Such investigations typically include interviews with or sworn statements from service members and witnesses or others involved in incidents in question, as well as reviewing available documentation or evidence. They should result not only in findings, but also recommendations. According to the CHMR DOD-I, investigations may be conducted instead of or in addition to civilian harm assessments.
Notably, an administrative investigation is not a criminal investigation. If at any time during an assessment or investigation findings indicate a war crime or other criminal activity, the matter should immediately be referred to the responsible military criminal investigative organization for further inquiry.
Assessing the Credibility of an Investigation
Command Environment and Commander’s Intent
In our research, we found that the prevailing command environment can significantly shape both the scope and outcome of an investigation. This environment is expressed through formal and informal signals of a commander’s intent. One retired military member interviewed reflected that, “the command environment is going to shape what the commander deems worthy of inquiry.”
In the case of the Minab school strike, it is appropriate and expected that the Pentagon has announced a formal investigation. However, it is also important to consider the command environment created by senior military leaders. Secretary of Defense Hegseth has famously denounced “stupid rules of engagement.” He has spoken of giving “no quarter” in Iran, an approach that is specifically prohibited under international humanitarian law. In the context of the Minab strike, he has repeatedly made comments stressing that the United States does not target civilians. However, deliberately targeting civilians should not be the threshold for serious concern and inquiry into civilian harm events, nor is it required for an incident to constitute a violation of IHL or war crime. Recklessly doing so, or killing civilians through gross negligence, could also rise to that level.
In particular, under IHL, an attacking force must take all feasible precautions to avoid civilian harm, and “constant care must be taken to spare the civilian population, civilians and civilian objects.” In 2023, the Department of Defense updated its Law of War Manual (which sets out the department’s official legal guidance for its personnel carrying out military operations), clearly stating that the obligation to take feasible precautions “is a legal requirement.” Under the rule of proportionality, it must not launch an attack if the loss of civilian life, injury to civilians, and damage to civilian objects would be excessive compared to the concrete and direct anticipated military gain. The deliberate or reckless failure to take feasible precautions is also a war crime.
A command environment that ignores or degrades IHL would almost certainly give rise to increased civilian harm and possible IHL violations, and could easily compromise the integrity of an investigation. At this stage, ensuring the integrity, thoroughness, and transparency of an investigation, rather than signaling a predetermined outcome, is necessary to ensure its credibility.
Scope
Army Regulation 15-6 and other command-directed administrative investigations are conducted by an investigating officer, in accordance with both the applicable regulation guidance as well as the instructions laid out by the commander in the appointment order.
Based on our research and experience, the appointment order should ensure that the investigation answers key questions such as:
- What was the intended target of the attack?
- What civilian harm occurred, including civilian deaths, injuries, and damage to or destruction of civilian objects?
- Why did civilian harm occur? What led to civilian harm?
- If an error in target identification or verification occurred, why did it occur?
- What precautions were taken in the attack? Was the duty of constant care exercised? At what point in the targeting process, if any, was compliance with these obligations assessed?
- Was civilian harm foreseen prior to undertaking the strikes? If so, did the military determine that this harm was proportionate to the expected military advantage, and how did it do so?
- What steps were taken to prevent or mitigate the risk of civilian harm in the strikes? Were these steps effective?
- What steps were taken to assess the pattern of civilian life in the targeted area before conducting the strikes?
- How did the U.S. military first become aware that civilian harm had occurred? (That may help reveal potential flaws in intelligence and information gathering prior to the strike and gaps in civilian harm reporting — and where improvements are needed.)
- Did the operation comply with the rules of engagement or other applicable guidance?
- Did the operation comply with IHL, also known as the law of armed conflict? Is there evidence that a violation of IHL may have occurred?
- What information does the U.S. military have regarding the identities of those harmed and their families? What post-harm responses or amends are possible?
- What lessons can be learned? What does the investigation recommend to ensure a similar incident does not happen in the future?
- In particular, for this incident, does the military’s system for gathering and evaluating intelligence adequately support operations in populated cities and towns? Does it meet law of war standards set by state practice and authoritative legal interpretation?
- If wrongdoing is identified, what disciplinary action should be recommended?
Independence
To reduce the risk of bias, an investigation should be as independent as possible. The CHMR DOD-I requires that any unit tasked with a civilian harm assessment, if not the command’s Civilian Harm Assessment Cell (CHAC, required under the DOD-I), must not have been directly involved in the civilian harm incident. However, the DOD-I does not make such a specification for investigations.
In the context of an AR 15-6 or other command-directed investigation, independence means that the investigating officer should be outside of and independent from the unit involved in the civilian harm incident in question. According to Hegseth, the investigation into the Minab school strike will be led by a U.S. general officer from outside CENTCOM, meeting this criteria.
Appropriate Training and Expertise
Our previous research found that investigating officers in AR 15-6 investigations too often lacked key training needed to carry out an effective investigation. Investigating officers are typically assigned to investigations from other duties, and may lack investigative competencies such as interviewing skills, as well as technical or thematic expertise related to civilian harm.
In addition to clear guidance and instructions in the appointment order, as described above, the commander in charge of the investigation should ensure that the investigating officer has the requisite skills to credibly complete the investigation as well as access to supplementary expertise, such as support from the DOD Civilian Protection Center of Excellence. (Notably, the Pentagon has significantly slashed civilian harm mitigation staff at the Center and across the combatant commands, losing valuable expertise and capabilities in the process.)
Use of Military Records
Our analysis found that the military has frequently relied on flawed or outdated records to inform investigations (as well as, in many instances, to inform strikes in the first place). In the case of the Minab school strike, where reporting indicates the targeting was based on intelligence more than a decade old, any investigation should scrupulously review and cross-check military records used against multiple sources of evidence, including ground information and external information.
External Sources & Witness Interviews
Our research found the U.S. military tends to rely primarily on internal records and sources when assessing civilian harm, and rarely seeks information from witnesses or survivors of attacks or visits the site of strikes. We also found the U.S. military tends to be highly skeptical of external information, such as reports from civil society and the media. These groups often have access to information that DOD lacks, including from witness and survivor interviews, site visits, and meticulous background documentation. A Pentagon-commissioned RAND study released in January 2022 similarly concluded that DOD relied on incomplete data in conducting its civilian harm assessments and investigations.
Recognizing these shortcomings, the Civilian Harm Mitigation and Response Action Plan (CHMR-AP) and CHMR DOD-I emphasize the importance of considering all information, including from external sources such as civil society, the media, and other open sources, in civilian harm assessments and investigations. As the Defense Department conducts ongoing 15-6 investigations, it should not rely solely on internal military records and interviews with personnel involved in planning and carrying out the incident. Instead, it should give significant weight to external reporting that includes information the U.S. government lacks, such as original interviews, photographs, and video. Where possible, the department should endeavor to conduct interviews with civilian witnesses and survivors, and solicit information from them or their representatives. Such interviews can be conducted remotely via phone or video. First and foremost, interviews should only be undertaken with the informed consent of civilian witnesses and survivors, and following a safety and security assessment to ensure their participation does not put them in danger. The department should also undertake measures to protect the identities of any civilian witnesses and survivors whose information is referenced in the investigation report and any public statements.
Recommendations: Amends, Accountability, and Lessons Learned
As part of a command-directed investigation, investigating officers can include recommendations for further action; and indeed, as noted above, the appointment order should ensure that recommendations are required. Recommendations that should be given special attention include post-harm amends, individual accountability measures, and lessons learned to reduce the risks of future civilian harm.
Amends for civilian harm can take multiple forms, including acknowledgement and apologies for harm, ex gratia (condolence) payments, and other assistance in accordance with the needs and preferences of victims and survivors. Accordingly, CHMR DOD-I provides that the DOD can respond to civilian harm by acknowledging harm suffered and the U.S. military’s role in that harm, expressing condolences to civilians, and helping to address the harm suffered. Responses noted in the policy include, but are not limited to, ex gratia payments, medical care, and repairs to damaged structures and infrastructure.
As part of the ongoing investigations into civilian harm, investigating officers should recommend the offer of amends in consultation with the victims and survivors or their representatives. (Notably, to safeguard the privacy and security of the civilians affected, the Defense Department should not announce publicly any specific plans regarding amends — such as issuing direct apologies or ex gratia payments — unless or until it determines, in conjunction with civilian victims and survivors or their representatives, that doing so will not subject them to new threats.)
The investigation should also recommend individual and institutional accountability measures if it finds that wrongdoing occurred. For example, violations of rules of engagement or other policies or procedures should result in disciplinary action. Potential violations of domestic or international law, including potential war crimes, should be promptly referred for criminal investigation.
Lastly, none of the accountability steps outlined here can bring back a lost loved one. True accountability must include steps to ensure that such incidents do not recur in the future. To that end, the investigation should include identified lessons learned and recommendations to prevent future harm, including procedural reforms, staffing changes, or further inquiries.
Public Communications and Transparency
Far too often, U.S. military leaders have reflexively denied initial reports of civilian harm, only for investigations by the media, civil society, and the U.S. military itself to prove otherwise. U.S. government and military leaders should ensure that public statements do not undermine or presuppose the results of an investigation. Rather than responding to civilian harm with knee-jerk denials of responsibility, they should focus on transparency, accountability, and understanding what happened and why. In this regard, the administration has already failed: President Donald Trump initially blamed Iran for the deadly school strike, only for the claim to be almost immediately debunked and walked back.
When investigations are completed, DOD should immediately and publicly release the full investigations and their findings, with minimal redactions only to protect the privacy and security of individuals or narrowly as required to protect national security. In so doing, the department should clearly communicate what happened in the incidents under review, whether any wrongdoing was found, and what steps will be taken to respond to the incident and prevent similar recurrences in the future.
* * *
Both Congress and the general public should have the opportunity to decide whether the Pentagon investigation into the Minab school strike — as well as any other ongoing investigations — was thorough and credible. This is an essential part of public trust and accountability. And more importantly, it’s the minimum owed to the victims and survivors of the catastrophic incident and their grieving families. If Congress does not deem the investigation sufficiently thorough or credible, particularly when evaluated against independent external reporting, they should conduct robust oversight in pursuit of truth and accountability, including through hearings and an independent congressional inquiry.
