OAKLAND — A reputed gang member on Friday was sentenced to 13 years in prison for killing another man in 2013 in an alleged retaliatory act to avenge a friend’s death.

Billy Joe Drinkwater, 33, pleaded no contest to voluntary manslaughter and gun use in the fatal shooting of 20-year-old Malik Birchett under a plea deal that was offered by prosecutors during his murder trial this summer.

Prosecutor Chris Cavagnaro didn’t comment Friday on the reasons for the plea offer, but defense attorney Alex Harper told the judge that the case against Drinkwater had “problems.”

Birchett’s family said in court Friday that they were unhappy with the sentence. Drinkwater would have faced more than 50 years to life in prison had he been convicted as charged by the jury.

Authorities said Drinkwater fired into a car containing Birchett and two friends, including Desmond Provost, while they were stopped in the 600 block of 55th Street in North Oakland because Drinkwater thought they were connected to the death of his associate, Lorenzo Ward.

Provost was charged with murder in Ward’s slaying on Sept. 1, 2012, in North Oakland. He pleaded down to manslaughter and awaits his sentencing. He had been scheduled to testify against Drinkwater but had not yet taken the stand before Drinkwater’s trial came to a halt.

Drinkwater’s driver during the shooting was Keiar Robinson, the son of two former Oakland police officers. Harper accused the Oakland Police Department of overlooking evidence because of the familial connection. For example, Oakland police searched Robinson’s vehicle, but not his home, where he lived with his parents.

Birchett’s family expressed loss and forgiveness in their statements in court. They said Birchett, the father of a young girl, played an important role in their family, and they hope something positive comes from the tragedy.

“I want people who know him and know my brother to change from this,” Birchett’s sister told the judge.

Contact Malaika Fraley at 925-234-1684. Follow her at Twitter.com/malaikafraley.