TULSA, Okla. — Update: Tulsa Police arrested Celestine Mason for first-degree murder and threatening an act of violence on Monday.

Tulsa police are looking for a woman identified as the second suspect in a north Tulsa homicide.

They’re searching for 27-year-old Celestine Mason in connection with the killing of Trayvis Watson.

Police arrested 26-year-old Keith Stewart for first-degree murder on Monday.

The shooting happened last Tuesday, July 2 near 46th Street North and M.L.K. Jr. Blvd.

Police said 51-year-old Trayvis Watson was shot in the head during an altercation and died.

Detectives learned Mason was living in her van in the backyard of Watson’s home for about a week before the homicide.

If you have information that can help police find Mason, you’re asked to call Tulsa Crime Stoppers at 918-596-COPS (2677).

Tulsa Police arrested 26-year-old Keith Stewart for first-degree murder after a man was shot and killed in the backyard of a north Tulsa home.

Police said officers found 51-year-old Trayvis Watson with a gunshot wound to the head in the backyard of a home near 46th Street North and M.L.K. Jr. Boulevard.

Police said Watson got into an argument with Stewart and another man and was shot after the altercation escalated. Watson managed to run back into his house where he died.

Police said the investigation is still ongoing