THE FINDINGS of the U.S. Attorney’s investigation into the death of a young mother after a harrowing car chase on Capitol Hill settles the issue of whether there was criminal or civil rights culpability. Prosecutors said they found insufficient evidence that the two officers who shot Miriam Carey used excessive force or had criminal intent. That there will be no criminal prosecution leaves unanswered a critical question: Was there a better, nonlethal means of dealing with the situation?

The responsibility for answering that question lies with the two federal police agencies involved in October’s pursuit of Ms. Carey. It is important they respond in a way that is as transparent to the public as possible.

Announcing the decision not to bring criminal charges, U.S. Attorney Ronald C. Machen Jr. issued a statement that detailed the frightening seven minutes of Oct. 3, 2013, when Ms. Carey attempted to breach security checkpoints at the White House and Capitol Complex, led police on a high-speed chase, hit a uniformed officer and attempted to run over another officer — all the while refusing to obey multiple commands to stop. It was later discovered that Ms. Carey had mental-health issues; her 1-year-old daughter who was in the car with her was unhurt.

Prosecutors typically do not announce a decision to decline to pursue criminal charges. The detailed statement of facts that summarized the events, accompanied by still photos from video footage, was acknowledgment of the unique circumstances of the case and the intense public interest.

We hope that point is not lost on the U.S. Secret Service and the U.S. Capitol Police and that they will be equally forthcoming once they complete their own administrative inquiries to determine if officers followed use-of-force policies and whether any changes in policies or practices are warranted. The agencies have been provided, according to a statement from Mr. Machen’s office, with “voluminous materials” gathered during the investigation, including ballistic reports and witness interviews.

What happened to Ms. Carey was a tragedy. Whether it was preventable or if there are lessons to be learned are questions still awaiting answers.