Authorities are offering a $5,000 reward for information leading to an arrest and conviction in the May slaying of a transient in Huntington Beach.

Police found 43-year-old Tyrrell "T-Rex" Louis Rathbun shot dead in an alley in the 300 block of Memphis Avenue hours after officers had responded to reports of someone yelling and setting off fireworks in the area.

At the time of the call, police said, they found nothing unusual. But an Orange County coroner's report found that Rathbun's death coincided with the time of the fireworks call — about 11 p.m. May 10.

His body was found at about 8:30 a.m. May 11, police said.

Rathbun was wearing a black hooded sweatshirt and gray athletic shorts with blue trim, according to police. He also had a black beach cruiser with a blue seat, and carried a heavy-duty orange extension cord on a spool.

Because Rathbun tended to move around the city, it has been difficult for investigators to piece together his final days, according to a Huntington Beach Police Department news release.

So, in partnership with Orange County Crime Stoppers, the department is offering the reward.

Anyone with information is urged to call Crime Stoppers at 1 (855) 847-6227, text 274637 (CRIMES) messages beginning with the letters "OCCS," or submit tips to occrimestoppers.org.

Information can be submitted anonymously.

—Jill Cowan