BATON ROUGE - A man being held in the East Baton Rouge jail was booked on new charges Thursday after police discovered he allegedly killed two people in less than a week.

The Baton Rouge Police Department said Mekhi Palmer-Davis, 19, was already being held in the parish jail when they pinned him as the suspected gunman in the April 24 shooting on North Donmoor Avenue. 

In that killing, Carlton Phillips, 21, was found shot to death inside his vehicle. Police said at the time they believed the shooting was drug-related. 

Palmer-Davis had already been in jail since July 1, when he was arrested in a separate shooting that happened April 30. In that case, police said Palmer-Davis shot and killed Raychard Flowers, 21, after getting into an argument at Flowers' home. 

Palmer-Davis was booked Thursday on a charge of first-degree murder. He was already facing charges of second-degree murder and illegal use of a weapon after his previous arrest.