Updated

Los Angeles police detained a "person of interest" late Sunday in connection with a spate of shootings that killed three people and left four others injured in the northern suburbs of Los Angeles earlier in the day.

LAPD spokesman Capt. William Hayes said the suspect was taken into custody by SWAT officers following a standoff that occurred when the man barricaded himself inside a house in Sylmar for about an hour. He declined said what led officers to the house or whether any evidence was found inside. Witness had reported seeing two men in a tan- or gold-colored SUV at two of the three crime scenes in the San Fernando Valley area. However, Hayes declined to say whether a second suspect remained at large.

"I can't tell you whether there was a second individual, we're following all clues and leads at this time," he said late Sunday.

Police said the victims appeared to be randomly targeted by the same gunmen because the same type of weapon was used in the morning attacks and the suspect shot at victims from inside a car.

In the first attack, a family of five riding in a car to attend church was struck by gunfire at 5:50 a.m. in San Fernando. The family had pulled over after noticing the suspect driving erratically when they were shot, Sgt. Frank Preciado, a police spokesman, said.

A woman in her 20s was killed, her mother and father were critically wounded and two children sustained minor injuries from either bullet fragments or broken glass, Preciado said.

At about 6:35 a.m., a man was fatally shot at a Sylmar park. The Los Angeles Times reported that the man had been looking for recyclables and was shot as he walked toward the suspect vehicle in the parking lot.

Then 15 minutes later and less than 5 miles away, a woman in her late 50s who was sitting in a parked car by a church was shot in the head. Preciado said she may have been waiting for someone, but he didn't have more details. The Times reported that friends had identified the woman as 59-year-old Gloria Esparanza Tobar. None of the other victims' identities had been released.

The shootings triggered an intense investigation and prompted the Los Angeles Police Department and Los Angeles County Sheriff's Department to step up patrols on the street.

"It's a major threat," Preciado said.

He urged people to be vigilant until the suspects are apprehended.

"If you see someone that matches that description or their vehicle matches that description, then go off to an adjacent street," he said. "Get away."

Investigators were looking into whether Sunday's attacks were related to at least two shootings earlier in the week, Preciado said.

The Associated Press contributed to this report. 

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