Austin police are investigating a homicide after a body was found in the Onion Creek greenbelt in Southeast Austin on Sunday evening, police said.

Police got a call from someone who spotted the corpse while walking their dog around 6:30 p.m. in a secluded area near the intersection of Onion Creek Drive and Springville Lane. The victim, described as a man in his 30s, had obvious signs of trauma to his body, although a cause of death has not yet been released.

Police said they believed the death happened less than 24 hours from when the body was discovered.

“We think we have an idea of how it happened, but we’re not going to release those details,” officer Marcus Davis said Sunday night.

Police have not yet identified a suspect or determined a motive for the killing.

“We do believe that this is an isolated incident,” Davis said. “It does not appear that there is any danger to the public.”

Police are asking anyone with information related to the crime to call 911.

“It was pure luck that we had someone that was walking their dog in this area to come across that,” Davis said.