The House and Senate Armed Services Committees are scrutinizing a Sept. 2 attack by the U.S. military on a speedboat in the Caribbean Sea that the Trump administration has claimed was smuggling drugs — and especially whether a decision to fire a second missile at the vessel, which killed two survivors of the first blast, was a war crime.

The oversight effort is dissecting the specific orders of Defense Secretary Pete Hegseth and the Special Operations commander overseeing the attack, Adm. Frank M. Bradley. The admiral and Gen. Dan Caine, the chairman of the Joint Chiefs of Staff, are scheduled to go to Capitol Hill on Thursday to answer questions about the strike.

A broad range of legal experts argue that the killings have been murders.

The Trump administration insists that its lethal campaign, including the second strike on Sept. 2, is lawful.

Here is a closer look.

What is the boat attacks operation?

President Trump has ordered the military to kill people on boats in international waters who are suspected of smuggling narcotics on behalf of drug cartels. Since Sept. 2, the administration has announced 21 such attacks in the Caribbean Sea and the eastern Pacific Ocean that have killed 83 people.

This is a change from the longstanding U.S. approach of having the Coast Guard intercept such vessels and, if suspicions prove accurate, seize illicit cargos and arrest the people on board. The legality of the new policy has been widely disputed.

What is the legal dispute?

The Trump administration says the operation is lawful because Mr. Trump “determined” that the United States is in a formal armed conflict with drug cartels, even though Congress has not authorized one, and that people suspected of running drugs are “combatants.”