Petaluma police have arrested a 19‑year‑old Santa Rosa man suspected of stabbing to death an acquaintance during a fight at a Sonoma State University dorm apartment Sunday night.

Tyler J. Bratton, was arrested on suspicion of murder in the death of a 26‑year‑old Sonoma County resident — neither were students at the college, Petaluma police Lt. Tim Lyons said Monday during a press conference outside the campus police station.

Bratton was booked into the Sonoma County Jail Monday morning and held without bail.

The victim’s name wasn’t released pending notification of family, Lyons said.

The two men were on campus to visit friends and an altercation arose in front of at least one witness, Lyons said. “This is not a random act. Everybody involved knew each other.”

Sunday’s stabbing happened just before 6 p.m. in the Sauvignon Village of dorm buildings for freshmen students on Redwood Circle Drive. The victim was found amidst a bloody scene in an upstairs apartment of the Alicante building. He was declared dead at 6:06 p.m. and a suspect in the area was detained and later arrested, police said.

Petaluma detectives are leading the investigation, working with Sonoma State University police.

Officers found a knife they believed to be the weapon. Monday officers and detectives were interviewing people in the dorm area at the time and seeking search warrants, including for cell phones, Lyons said.

“All of us at Sonoma State are shocked and saddened by this tragic event. Our hearts go out to all who’ve been impacted,” Sonoma State University President Judy Sakaki said during the press conference. “Our focus today will be continuing to make sure the needs of our students and our campus community are met.”

On Sunday the Alicante dorm building was off limits for the investigation. Displaced students were offered lodging at area hotels, but all declined, finding space with friends and family, said Paul Gullixson, univerity spokesman.

Monday morning all of the dorms were open except the one where the stabbing occurred. “Campus life is going on as usual,” Gullixson said.

Grief counseling was available to students and faculty. The death occurred on the eve of the semester finals’ week and those facing finals while struggling with the violence were being told to contact professors, said Gullixson.

Check back for updates.

You can reach Staff Writer Randi Rossmann at 707‑521-5412 or randi.rossmann@pressdemocrat.com. On Twitter@rossmannreport.