PICO RIVERA, Calif. » A 16-year-old girl used her last words after being stabbed in her Los Angeles-area home to scream the name of the ex-boyfriend she broke up with two weeks ago, helping make him a suspect in her death today, according to the lieutenant in charge of the investigation.

The girl’s screams woke her mother up and roused neighbors from sleep just after 3 a.m. in the quiet neighborhood in Pico Rivera, about 10 miles southeast of downtown Los Angeles, Lt. Eddie Hernandez said.

Elena Moore had been stabbed at least once in the chest, and she collapsed and died in front of her mother a short time after yelling the name “Rory.”

“She was yelling and screaming his name. It’s horrible,” Hernandez said. “Can you imagine waking up to the screams of your daughter at 3:15 in the morning and this happens? It’s unthinkable.”

Investigators were searching for Elena’s 17-year-old former boyfriend, Rory Murga.

Evidence found at the crime scene also tied Rory to the home, Hernandez said.

Two photographs of Murga were released after investigators searched for him for 12 hours. One showed him with short green hair, and the other one pictured him with longer black hair with a section of bangs dyed light brown.

A kitchen knife believed to be the weapon used in the attack was recovered inside the home, Hernandez said.

It was unclear whether Elena let her killer into the home or whether the attacker broke in, he said, adding that damage found to the back door could have happened in the past.

The stabbing happened downstairs, and Elena was able to run upstairs to her mother before collapsing, Hernandez said.

Elena, also was known as Lily, and Rory dated for a year until she ended the relationship two weeks ago, he said.

Elena’s Facebook page showed that she began a relationship with Rory last September, but there are few other signs of their connection.

Kara Wilson, a 15-year-old Palm Bay, Florida, girl who said she was online friends with Elena, said Elena never mentioned a boyfriend and that she’s in shock over her death.

“At first I didn’t believe it happened to her so I tried to call her,” Kara said. “She didn’t answer.”

She said Elena stood out among all her friends because she never posted anything negative on Facebook and even defended those who were being subjected to bullying.

“She was always sticking up for people,” Kara said. “She was the sweetest.”

Elena’s home was encircled Friday afternoon with crime-scene tape, and sheriff’s investigators were seen taking bloodhounds inside to help them search for the killer. The middle-class block of homes is just down the street from a church and several schools.

Twenty-year-old Jasmine Gonzalez, who lives nearby, often saw Elena and Rory walking together in the neighborhood.

“It was always just them two,” she said, adding that her grandfather woke to the girl’s screams, as well. “It’s a shock to everybody.”

Another neighbor, 60-year-old David Arias, saw the couple hanging out in front of his house from time to time.

“They seemed happy and lovey dovey,” he said. “Always hugging and kissing.”