SAN DIEGO -- A young man and a teenage boy were behind bars Tuesday on suspicion of murder in connection with the apparently gang-related weekend stabbing of a Mountain View resident near his home.

The 14-year-old was arrested at a Chula Vista residence late Tuesday morning for allegedly taking part in the slaying of 48-year-old Emiliano Cortez of San Diego, according to police. The suspect's name was withheld because he is a minor.

About 11 a.m. Monday, detectives arrested 20-year-old Josue Hernandez Gutierrez outside a friend's house in the 7100 block of Mohawk Street in the College area, SDPD Lt. Kevin Rooney said.

Gutierrez and the teenager allegedly attacked Cortez about 4:45 a.m. Saturday as he was walking in the 3700 block of T Street, near Mount Hope Cemetery and about a half-mile from the home where the victim lived with relatives. Medics took the gravely wounded man to a trauma center, where he was pronounced dead less than an hour later.

Police disclosed no suspected motive for the slaying, except that it was believed to be gang-related. There was no evidence that a robbery or other crime was involved, Rooney said.

Residents of the area where the killing occurred told investigators a loud argument and a man's screams prompted them to look outside, at which point they saw someone lying on a sidewalk and two people running off to the east.

It was unclear why Cortez was walking through the inner-city neighborhood just east of downtown San Diego, though he apparently was not on his way home.

"We have no idea where he was headed,'' Rooney said.

The suspects also live in the same general area, the lieutenant said.

Gutierrez was being held in county jail, and the underage suspect was to be booked into juvenile hall Tuesday afternoon.