A reward of up to $10,000 is being offered to help find the person responsible for killing an 18-year-old Gwinnett County boy, police said Tuesday.

William “Slade” Petty, a recent North Gwinnett High School graduate, died July 27 after being stabbed multiple times outside his Suwanee apartment, according to police. Officers were called to the Residences at McGinnis Ferry shortly before 9 a.m. and found Petty dead, Suwanee police Lt. Robert Thompson previously said.

Investigators with the Gwinnett police department and sheriff’s office assisted with the investigation and search for a suspect, along with the District Attorney’s Office, Thompson said.

But a week later, no one was in custody, police said. Petty’s funeral was held Saturday.

“Suwanee police believe people out there know who perpetrated the murder and the circumstances surrounding what happened,” the agency said Tuesday in an emailed statement.

In addition to the Crime Stoppers Atlanta reward of $2,000, Petty’s family has contributed an additional $8,000, police said.

Anyone with information on the case is asked to contact Suwanee detectives at 470-360-6735. To remain anonymous, tipsters can contact Crime Stoppers at 404-577-TIPS (8477) or visit www.stopcrimeATL.com.