As Jawan Lloyd Billy awoke in a Baton Rouge home Saturday afternoon, he adjusted his pants — causing a gun tucked into his waistband to discharge, killing a man who also was waking up just feet away, according to police.

Now Billy, 19, has been booked into Parish Prison and accused of negligent homicide.

Billy and the victim, Demarcus Rheams, 20, were sleeping on the same couch in a garage apartment on Jefferson Avenue when the two began to wake up about 12:30 p.m., according to a police report.

Billy “attempted to adjust” his clothing, and in the process, the gun discharged, striking Rheams once in the side of his chest. Rheams was sitting next to Billy on the couch when the shooting occurred, the report says.

Rheams did not die immediately, police said. Billy tried to save him while he waited for medical staff to arrive, according to the report. But Rheams died at the scene.

“They didn’t have problems before,” Cpl. L’Jean McKneely, a Baton Rouge police spokesman, said Saturday of the two men. “It wasn’t purposely done.”

Billy told police that he had found the gun “by a canal near his home” — but a search of the gun’s serial number showed that it had been stolen, the report says.

Billy, 1955 Rice Drive, Baton Rouge, was booked into Parish Prison on counts of negligent homicide and possession of a stolen firearm.

A nephew of Billy, who declined to give his name, said Sunday that the two men were close friends for years — and that Rheams had even spent part of Christmas Day at Billy’s house.

“Imagine how (Billy) feels,” the nephew said. “He killed his own friend.”

But, he added, his family “can’t feel bad” because Rheams’ family’s loss is so much greater.

Billy’s mother declined to comment, according to the nephew.

Rheams’ family could not be reached for comment.