IN BROAD daylight Saturday, two Prince George’s police officers opened fire in a residential neighborhood at a car containing a pair of unarmed burglary suspects. The suspects were allegedly trying to evade arrest on a leafy suburban street in Clinton, just southeast of the Beltway. As the suspects fled, their car apparently struck one of the officers, Garry Allen , a glancing blow; his knee was hurt. It’s not clear whether that happened before or after the officers opened fire. Witnesses said the street sounded like a shooting gallery. The officers fired at least seven shots , judging from recovered shell casings, and both suspects were hit.

In recent years, as crime in Prince George’s has plummeted, county police have seldom found it necessary to discharge their weapons in the line of duty. Last year, there were just four such incidents, down from 14 in 2011. That’s a remarkable measure of progress in a place that was beset with violent crime just a decade ago.

Police are certainly within their rights to fire their guns in self-defense or when they believe their lives or the lives of others are in danger. Yet in this incident, the justification isn’t clear. All the shooting was in one direction, and questions remain unanswered.

The officers responded to what appears to have started as a domestic incident involving one of the suspects, Carlos Thomas Barksdale, and a woman who called police. Mr. Barksdale is the father of her child. (Officers responded last September to a similar call from the same woman, who said Mr. Barksdale, who has faced previous criminal charges, had broken into her home, threatened her and brandished a gun. That information was transmitted to the officers who responded to the call Saturday, police say.)

When they arrived, the officers saw Darren Jones jump into a waiting car; Mr. Barksdale was behind the wheel. Police say the officers were justified in opening fire because Mr. Barksdale and Mr. Jones “used their car as a weapon” as the officers approached them.

Yet Officer Allen, the four-year veteran who was struck by the car, was not gravely hurt; he was treated for ligament injury and released the same day. So it seems reasonable to ask: On what basis did he believe his life was in danger? Was it necessary for the officers to fire repeatedly at the suspects, who did not return fire? Did the officers know or suspect that they were confronted with the same suspect who had allegedly brandished a gun in the same house last September? Did they (wrongly) believe he was armed again this time?

Before police can fill in the blanks, they may have to wait until the officers have obtained lawyers to represent them in a formal administrative investigation, as they are entitled to do under state law. At that point, the public deserves a full accounting.