2 Killed and 2 Injured in Separate Gang-Related Shootings Over Weekend : * Homicides: A 15-year-old is accidentally shot to death by a member of his own gang. Outside a Pacoima house, three people are gunned down.

Two northeast San Fernando Valley people were killed and two others injured in separate gang-related shootings, police said Saturday.

A 15-year-old was mistakenly shot and killed by another of his gang’s members, who police said was preparing to fire a shotgun at a pickup truck they were chasing through San Fernando.

San Fernando Lt. Rico Castro said Gustavo Villalobos Ponce, 20, of Arleta, was in custody on suspicion of murder Saturday after he shot his friend, Javier Martinez of Pacoima.

Castro said Ponce and Martinez were traveling in an Olds Cutlass that was chasing a pickup north on Hubbard Avenue near 4th Street around 10:15 p.m. Officer Lance Steaman saw the two vehicles and pursued them, he said.

Steaman followed the Cutlass as it turned right on 5th Street, Castro said. The car stopped on Orange Grove Avenue after hitting a parked vehicle. Steaman said he saw a shotgun thrown out the passenger’s window.

As he approached the car, Steaman saw Ponce slapping Martinez’s face in an apparent attempt to revive him, Castro said. Martinez had been shot in the leg.

Ponce, the passenger, had apparently been pointing the shotgun down as Martinez attempted to drive past the other vehicle, Castro said. But the gun fired instead into the femoral artery of Martinez’s leg, Castro said.

Martinez was taken to Holy Cross Medical Center, where he died.

Police on Saturday were searching for the pickup. Further investigation revealed that the Cutlass had been stolen two days earlier in North Hollywood.

In a separate incident, gunshots fired by suspected gang members in a drive-by shooting struck three people standing outside a Pacoima residence, killing one man and wounding two teen-agers, police said.

Police said the three victims were standing outside a house in the 10500 block of El Dorado Avenue about 11 p.m. Friday when the shots were fired. All three were transported to Pacifica of the Valley Hospital.

Francisco Gonzales, 24, of North Hollywood, died from a single gunshot wound to the upper torso, authorities said.

A 14-year-old boy and a 16-year-old girl, who both suffered minor gunshot wounds, were treated and released.

Detectives had not determined whether any of the victims were gang members. No arrests had been made.