A Renton man who shot and killed an 18-year-old as he ran from the scene of a failed drug robbery was sentenced Friday in U.S. District Court in Seattle to 10 years in prison and four years of supervised release.

David Steven Ross, 36, pleaded guilty to three federal felonies: conspiracy to distribute marijuana, possession of a firearm in furtherance of a drug trafficking crime and unlawful possession of a firearm.

“The fact that you brought that firearm to a volatile situation, knowing it was suspicious…. You should have walked away,” U.S. District Judge Robert S. Lasnik said at the sentencing hearing.

“This case is a grim reminder that drugs and guns don’t mix,” said Acting U.S. Attorney Annette L. Hayes. “No matter what the drug, we will not allow the violence that comes from this dangerous combination to go unpunished. That is especially true when – as in this case – the gun is in the hands of a convicted felon.”

According to the records filed in King County Superior Court and federal court, Ross and an associate arrived at a Federal Way apartment complex to sell two pounds of marijuana to two men – Lenny Brikn and his brother, Deshawn Boykin.

Ross was armed with a stolen gun, despite having two previous felony drug convictions that prohibited him from possessing a firearm. Brikn and Boykin drew “Mac 10” style semi-automatic pistols, ordered Ross and his associate to lie on the ground, and attempted to rob them of the marijuana.

Ross claimed to be an undercover police officer, and scared Brikn and Boykin into running away. As the two would-be robbers fled, Ross drew his gun, aimed and fired multiple times at the men.

Boykin was hit twice in the back and died of his wounds at St. Francis Medical Center.

Lenny Brikn, Jr., 20, of Federal Way was sentenced last September to seven years in prison for Possession of a Firearm in Furtherance of a Crime of Violence & a Drug Trafficking Crime.

-From a press release