Caleb said Patrick Eli Morris, 19, could be in Oakland, Calif. Morris is originally from that city and his mother drove him to California on Saturday to visit his father.
Detectives believe Morris shot Diego Aguilar late Friday in the upper parking lot of Rivers Inn motel. Aguilar died at the scene.
Morris will be formally charged with murder on Monday, Caleb said. Four other people, including a juvenile, were arrested Saturday for their alleged roles in the crime. Trevor Levi Parker, 20; Steven S. Vannarath, 18; and J.D. Cobb, 19, and a 17-year-old are charged with hindering prosecution. The three adults were being held at the Klamath County Jail in lieu of $500,000 bail.
Caleb said some of the suspects appeared to know Aguilar, and detectives believe there may have been a prearranged fight.
Aguilar of Lancaster, Calif., had been in Klamath Falls for a couple of weeks and was living with his mother at the motel, authorities said.
Investigators recovered the suspected murder weapon, a sawed-off 12-gauge shotgun, a couple of blocks from the murder scene.
An autopsy was scheduled for Monday.
Cassandra Coons, who lives near the motel, said her husband called 911 after the couple heard four gun shots while watching a movie in their living room.
"It almost sounded like a cannon going off," she said.
The couple saw two men run toward the motel entrance and another man run toward their house and hop a fence. After the gunshots, Coons said she saw a woman standing in the parking lot shouting, "My son is dead! My son is dead!"
Information from: Herald and News, http://www.heraldandnews.com