A 15-year-old girl who endured sexual abuse as a child in her El Monte home at the hands of her mother and four men living with them was awarded $45.4 million Thursday in her lawsuit against Los Angeles County, which alleged two social workers had reasonable suspicions she was being molested but failed to inform authorities.

A Los Angeles Superior Court jury deliberated for about 4 1/2 hours before reaching its verdict in favor of the teenage plaintiff. The panel apportioned the county’s liability at 45 percent, or about $20.6 million. The jury delegated another 45 percent responsibility to the child’s mother and 10 percent collectively to the four male perpetrators.

Plaintiff’s attorney David Ring said he hoped the jury’s verdict will prompt change in the way county’s Department of Children and Family Services social workers do their jobs so as to better protect children who may be vulnerable to abuse.

Christie Bodner Swiss, an attorney for the county, declined to comment.

In his final argument Wednesday, Ring said the case was about “the destruction of a girl’s life. You heard about how abusive the sexual abuse of (the plaintiff) was.”

Ring called the county’s department of children’s services “the last line of defense for defenseless children” like the plaintiff.

But although two DCFS social workers had reasonable suspicion the girl was being sexually abused because one of the male residents of her apartment had a past arrest record, they did not call the county hotline or notify El Monte police, Ring argued.

“They could have prevented this from happening — they should have prevented this from happening,” Ring said.

Tomas Guterres, another attorney for the county, told jurors it is the DCFS’ mission to keep children safe. But he said Ring overstated the agency’s responsibilities.

“That front line can’t be placed on the DCFS; it has to be the parents, one or the other,” Guterres said, asking why the child’s father did not show more parental leadership.

The teen’s father is her legal guardian and filed the lawsuit on her behalf in Los Angeles Superior Court in June 2013, alleging DCFS social workers Elbis Severo and Lucia So didn’t take steps to have the girl removed from the Arden Way residence in 2010, despite having a reasonable suspicion that the then-Gidley Elementary School student was being molested.

The girl now lives in New Mexico with her 35-year-old father and soon will begin her sophomore year in high school.

Although Ring argued Severo rushed to close the abuse case in November 2010, lawyers for the county maintain that social workers had no grounds to seek removal of the child from her mother until 2012, when the girl confided in her father’s girlfriend at the time that she had been abused.

Ring said one of convicted men, Louis Fluet, moved into the El Monte apartment where the abuses occurred not long after the girl, her mother and her two half-sisters moved there from Temple City because of abuses committed by the mother’s husband at the time.

Fluet had a past arrest record for child sexual abuse, Ring said.

Fluet at first had his own room, but he later began sleeping on a separate bed in the same room where the plaintiff stayed, he said. The social workers learned in 2010 that he had been arrested in the past for annoying or molesting a minor, but did not take sufficient steps to ensure he was removed from the apartment, Ring said.

“He continued to molest that girl for basically the next 24 months,” Ring said.

Ring called the male abusers “scorpions and predators” and said the child’s mother allowed her daughter to be abused by them so that she could obtain drugs.

Guterres said DCFS social workers choose their type of work over jobs where they could face less pressure and receive higher pay.

“They do it because they have a passion for it,” Guterres said.

The girl’s mother, now 39, and the four men were convicted of sexually abusing the plaintiff, at least two of which were incarcerated.

The mother is out of custody but must register as a sex offender for life.