SAN DIEGO — One year after a San Diego man was gunned down at a community park, authorities put out a call for information on his killer this week.

Luis Alberto Arroyo, a 38-year-old, was shot and killed around 2 a.m. on July 26 of last year, according to San Diego County Crime Stoppers. The killing happened in the Emerald Hills area of southeast San Diego.

That night, officers drove to Emerald Hills Park — near Kelton Road just south of state Route 94 — after a caller reported gunfire nearby, officials said. They found Arroyo suffering from gunshot wounds in the parking lot and gave him CPR until the fire department arrived to take over. Paramedics eventually rushed him to the hospital, but he was pronounced dead a short time later.

In the year since Arroyo’s killing, the San Diego Police Department Homicide Unit has been trying to figure out what led up to the shooting and who was responsible. Months later, little is known.

In a news release Thursday, investigators put out another call for witnesses and any other information that could help solve the case.

Police urged anyone with tips to call the Homicide Unit at 619-531-2293 or the Crime Stoppers anonymous tip line at 888-580-8477. The organization also has a dedicated website.