JACKSONVILLE, Fla. – A 35-year-old convicted felon already being held on a firearm charge has now been charged with murder in the May shooting death of a 28-year-old man in Jacksonville, according to the Jacksonville Sheriff’s Office.
Mark Mulliens, 35, is accused of killing Jarrius Brown, 28, following a fight at a home near Beach Boulevard.
Jacksonville police responded May 17 to a residence on Mayfair Road after receiving a report of a shooting. Officers found Brown suffering from a gunshot wound.
Brown was rushed to a local hospital, where he later died.
According to the sheriff’s office, homicide detectives determined Brown and Mulliens had been involved in a fight earlier that afternoon. Investigators said the confrontation escalated and Mulliens shot Brown before fleeing the scene.
Detectives reviewed surveillance video and interviewed witnesses as they investigated the shooting. JSO said that evidence was used to build its murder case against Mulliens.
Investigators initially arrested Mulliens 10 days after the shooting on a charge of possession of a firearm by a convicted felon. He has remained in the Duval County Jail since that arrest.
JSO said Mulliens has four previous prison sentences stemming from drug trafficking and armed robbery convictions and had most recently been released from prison in 2025.
While Mulliens remained jailed on the firearm charge, homicide detectives continued investigating Brown’s death. On Sept. 23, detectives formally arrested him on the murder charge.
The sheriff’s office did not provide additional information about what prompted the initial fight between Brown and Mulliens or disclose whether the two men knew each other before the encounter.