Authorities launched a homicide investigation after a man from the East Bay was found fatally shot off the side of a roadway in Napa County on Sunday morning.

According to the Napa County Sheriff's Office, a California Highway Patrol dispatcher received a call around 9:40 a.m. about a potential fatality near the 2600 block of Monticello Road, in the hills east of Napa. A caller reported that a man with blood on his clothes was not moving.

Deputies arrived less than 10 minutes later and located the man, who was pronounced dead at the scene. The man was shot multiple times.

The sheriff's office identified the victim as 20-year-old Salvador De Jesus Castillo-Hernandez, a resident of Concord.

In a statement on Monday, deputies said the motive and circumstances surrounding the shooting are not known at this time, but that a suspect was arrested. 

The sheriff's office identified the suspect as 22-year-old Bryna Alexis De Paz Gomez, also known as Bryan Gomez. He was arrested on suspicion of murder in Napa, around 2 p.m. According to the sheriff's office, Gomez is from Vallejo.

Anyone with information is asked to contact Detective Phil Tieu of the Napa County Sheriff's Office at 707-253-6030 or by emailing philip.tieu@countyofnapa.org.