HAYWARD — A Hayward man turned himself in to authorities Thursday night after a fight over a female friend left an 18-year-old man dead after being stabbed with a knife, police said.

Erick Alexander Mayorga, 27, was arrested on suspicion of homicide — Hayward’s second slaying of 2011, Sgt. Steve Brown said.

Mayorga is being held in police custody and is expected to be arraigned Monday at the Hayward Hall of Justice, Brown said.

Authorities will not release the name of the deceased Hayward man until his family is notified.

After conducting preliminary interviews, police determined the incident began in the 900 block of Folsom Avenue, at the home of a woman who was a friend of the victim, who lived nearby. Mayorga is the woman’s ex-boyfriend.

“By all appearances, the neighbor was in a close relationship with the woman and he believed she was being disrespected by (Mayorga), and he didn’t like it,” Brown said.

The neighbor confronted Mayorga, a fight ensued, and as it escalated, Mayorga grabbed a knife and stabbed the man, Brown said.

“It was a fight that got out of hand,” he said.

Officers responding to a 7:38 p.m. call reporting a disturbance in the home discovered the severely injured man after he had stumbled outside and collapsed in front of the house, police said.

After firefighters and emergency medical technicians tried lifesaving techniques on him, he was taken to Eden Medical Center in Castro Valley, where he was pronounced dead at 8:41 p.m., police said.

Meanwhile, Mayorga had left the scene, but he took the advice of a friend and went to the police department later in the night to turn himself in, Brown said.

“The police investigation is still continuing and there are witnesses at the scene related to both parties who we still need to interview,” he said.

One neighbor, who requested anonymity for fear of retaliation, said a few men have been seen firing guns in the air not far from the same home where the fatal stabbing took place.

“As soon as I can leave this neighborhood, I will,” the neighbor said. “I don’t feel safe here no more.”

Anyone with information about the incident may call police at 510-293-7034.

Contact Chris De Benedetti at 510-353-7011.