ATLANTA (AP) — Three men have been convicted of killing a nephew of Atlanta's mayor-elect in a mistaken gang shooting.

Authorities have said 18-year-old Darius Bottoms was shot in the head because 23-year-old Ryan Bowdery, 22-year-old David Dajunta Wallace and 19-year-old Rashad Barber mistook him for a member of a rival gang.

All three were convicted Thursday of felony murder and other charges, Fulton County District Attorney Paul Howard Jr. said in a news release. Each was sentenced to life in prison, plus additional time.

Bottoms was a nephew of Keisha Lance Bottoms, who was elected Atlanta mayor earlier this month and takes office in January. His vehicle was ambushed; a passenger was unhurt.

His mother, Myeka Jennings, told WSB-TV the case reflects the magnitude of Atlanta's gang violence problem.

"Just to see where this city's going with gang violence, this is just a start. There's a lot of it going on," she said.

In addition to felony murder, all three men were convicted of criminal street gang activity and possessing a firearm while committing a felony. Barber and Bowdery also were convicted of malice murder, criminal damage to property and aggravated assault.

"I hope that people look and see how gang activity has really infiltrated our community," the district attorney said. "I could be standing here with any family in Atlanta because Darius Bottoms was not a gang member. He was not involved in any incorrect activity."

The case was tried twice. The first time ended with a mistrial after it was suggested a juror spoke with an Atlanta police detective about ballistics information during the trial, the Atlanta Journal-Constitution reported .