Son identified as suspect in Baldwin Park fatal shootings

A Baldwin Park man suspected in the shooting deaths of his mother, a neighbor and her 4-year-old daughter was twice detained and hospitalized by police before Monday’s rampage, authorities said Tuesday.

“The suspect apparently had some mental problems,” said Los Angeles County Sheriff’s Lt. Dan Rosenberg.

Roy Perez, 28, was arrested on suspicion of murder by Baldwin Park police late Monday night as he stood in the street holding a handgun.

He is accused of killing his mother, Alicia Rivera Perez, 47, and then breaking into a next-door neighbor’s home and fatally shooting Dalmy Perez De Mata, 31, and Briana De Mata.

Authorities said Perez also shot and wounded two of De Mata’s other children, a 14-year-old boy who remains in critical condition and a 9-year-old girl.

Authorities said Monday that she was in critical condition, but later learned she had been grazed by a bullet.

On Tuesday, authorities said it appeared that Perez had been arguing with his mother before gunfire erupted about 7:30 p.m. in the 14500 block of Rockenbach Street.

Investigators were unclear about the motive for the shootings, Rosenberg said.

But police had responded to the Perez home twice in recent years because of the suspect’s erratic mental behavior, he said.

“There’s no indications of any problems or bad blood or anything of that nature,” Rosenberg said of the slayings. “You got a 4-year-old girl who got murdered, so no matter what issues were there or not, you’re certainly not going to have them with a 4-year-old.”

Some neighbors said they never expected something like the slayings would happen on their quiet street.

“He was a very nice young man,” said a former neighbor, Lupe Murillo. “I didn’t see any signs.”

She described the suspect’s mother as a “good person, very hardworking.”

Veronica Rojas, 20, who lives across the street, said that on several occasions, Perez had followed her and friends to shops and other locations, yet never spoke to her.

“He just seemed weird,” Rojas said. “He was always at home. I didn’t see him talk to anybody. He didn’t have any friends.”

Rojas’ mother, Guadalupe Figueroa, 42, said she had befriended Perez’s mother. The two women would invite each other to family functions, she said.

Figueroa said Perez had an unnerving habit of squealing his tires as he sped off.

“He would always burn rubber, and that bothered me a lot,” she said.

She said she didn’t know the De Mata family, but often saw the mother and her youngest child walking together.

“I used to see the little girl,” she said, “her mom holding her hand. It’s very sad.”

hector.becerra@latimes.com