Suffolk County District Attorney Daniel Conley says officers acted properly when they fatally shot Darryl Dookhran on Dec. 7, 2013.

In a letter today to BPD Commissioner William Evans, Conley says Dookhran had opened fire on the officers - hitting one of them in the arm:

"The investigation revealed that Boston Police Officer Ryan Lenane and Sergeant Thomas Teahan fired their service weapons in the proper exercise of self-defense and the defense of others. Sergeant Teahan and Officer Lehane fired on Mr. Dookhran only after he shote Officer Lenane in the left arm. Mr. Dookhran then engaged Sergeant Teahan and Officers Lehane and William Traft (who did not fire his weapon) in an excahnge of gunfire in a thickly settled residential and commerical neighborhood. Under the circumstances, Sergeant Teahan and Officer Lenane acted reasonably and lawfully when they discharged their service weapons."

Conley's letter details what happened that afternoon. Three officers, all members of the Youth Violence Strike Force, were in an unmarked cruiser, heading to Ridgewood Street to look for a gun they thought might have been left there after a shooting the night before.

As they drove on Geneva, near Topliff and Westville, Traft spotted two men walking on the other side of the street, one of them Dookhran, whom Traft knew had been involved with firearms - and for whom a regional police clearing house had recently issued a bulletin, in which he was described as carrying a gun on a regular basis.

Because of that, the officers decided to have a chat with him. But when Teahan and Lenane got out of the cruiser, Conley writes, Dookrahan turned and began to run away. The two began to follow him - and Traft got out of the car and joined the chase. But Dookhran's companion, Christopher Murrain, stepped in their way, Conley continues:

"As Officer Lenane yelled at Mr. Murrain, the officer heard a gunshot and simultaneously felt something strike him in his left arm. Officer Lenane yelled that he had been shot and unholstered his gun. When Sergeant Teahan heard the shot, he, too, unholstered his gun and prepared to return fire. Images from a surveillance camera mounted outsited the Sobrino Meat Market at 416 Geneva Avenue depict Mr. Dookhran running in a northwesterly direction on Geneva Avenue and turning back to point a gun at Officer Lenane, who was pursuing him and whose gun was still holstered.

"As he ran up Westville Street, Mr. Dookhran fired a second shot back in the direction of the pursuing officers. Surveillance video from a second camera mounted on the Westville Street side of the Sobrino Market depitcs Mr. Dookhran pointing his gun back in the direction of the officers. During the course of the brief foot chase on Westville Street, Officer Lenane fired twice at Mr. Dookhran, and Sergeant Teahan fired either two or three times. One of the shots struck Mr. Dookhran in the side of his left arm, near the top and toward the front. Another shot struck Mr. Dookhran in the right side of his head, above and slightly in front of his ear. The bullet exited on the left of Mr. Dookhran's head. ... Mr. Dookhran fell on the sidewalk on the southern side of Westville Street. Officer Lenane approached the fallen Mr. Dookhran and disarmed him. ...

"Police called immediately for an ambulance. Emergency medical technicians and paramedics arrived within minutes. Paramedics pronounced Mr. Dookhran dead at the scene."