Man Convicted for Helping Kill Parents of Teen He Became 'Obsessed' with Via 'Furry' Group: DA

The girl's slain mother allegedly introduced her to world of furries ... before the teen's sisters, aged 6 and 9, woke up one morning to find their parents and a family friend all brutally murdered in the home.

A California man is facing life in prison for his role in the murders of three people in 2016 -- two of whom were the parents of a teen girl prosecutors say he became "obsessed" with after meeting via a group for "furries."

On Tuesday, Frank Sato Felix was convicted of three felony counts of first-degree murder and three felony enhancements of multiple murders, the Orange County District Attorney announced in a press release.

Per prosecutors, Felix faces a maximum sentence of life in prison without the possibility of parole and is scheduled to be sentenced on January 17, 2025.

Orange County District Attorney's Office

Felix's 'Obsession' Begins

Per the release, Felix met the teen girl at the center of the murders via the "furry" subculture, where adults dress up in animal costumes. According to prosecutors, it was the girl's mother, 39-year-old Jennifer Goodwill-Yost, who introduced her to the community.

At the time they met, Felix was 25; the girl also met a third man, 21-year-old Army mechanic Joshua Charles, via the subculture.

Prosecutors say Felix and the teen became "romantically involved" -- but Goodwill-Yost and her husband, the girl's stepfather, Christoper Yost, "disapproved of the relationship."

KHOU / Harris County Sheriff's Office

A friend who said she met the mother-daughter duo at a furry gathering told Army Times that several weeks before the murders, Jennifer had forbidden the girl from seeing Felix.

"To protect her daughter, Chris and Jenn were like, 'We don't want you to be friends with our daughter anymore,'" said Melinda Giles.

Prosecutors, meanwhile, say Felix "became obsessed with" the girl after meeting.

"[Felix] became despondent and angry and eventually formulated a plan," Senior Deputy District Attorney Seton Hunt told the jury during trial, according to the Orange County Register. "[Felix and Acosta] determined they would solve the problem by saving the 17-year-old from the clutches of her mother and stepfather by murdering them."

Hunt also claimed that after the breakup, Felix reportedly "cut his arm in front of the girl."

GoFundMe/Hartford Police Department

The 2016 Murders of Jennifer & Christopher Yost

According to prosecutors, Felix is the one who provided the ammunition and shotgun used to kill the three victims -- Goodwill Yost, her husband, and a family friend, Arthur "Billy" Boucher, who was staying at the Yost's home the night of the murders.

"On September 24, 2016, Acosta and Felix drove to the Yosts' Fullerton home to execute their plan to help the 17-year-old to escape the home until she turned 18," said the DA in their press release.

After Boucher went to sleep, the teen then allegedly went to wait in the truck with Felix, while Acosta went on a shooting spree. Prosecutors say he first shot Boucher, 28, in the head while he slept on the couch, before going upstairs and shooting the girl's mother in the face. Christopher Yost allegedly "attempted to escape," but was shot in the head while trying to exit to the "outside patio area."

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The three suspects then "fled" the area, returning to Felix's Sun Valley home, where prosecutors say they "burned their clothes and attempted to destroy their cell phones."

The three victims weren't the only ones home that night, however ... and the teen's 6 and 9-year-old sisters "woke up to find their parents dead along with their friend and called 911."

In the 911 call, one of the girls reportedly said, "My dad is outside in the backyard dead, my mom is in her bed dead."

Cowlitz County Sheriff's Office/Facebook

The Aftermath

Felix was later arrested at his Sun Valley home, while Acosta was apprehended at his barracks at Fort Irwin.

During Acosta's trial, the teen testified, claiming she was molested by her stepfather and Felix had "blackmailed" her into having sex with him by threatening to tell her mom about the alleged abuse -- according to the Orange County Register. As the East Bay Times noted, prosecutors have said there's no way to verify those allegations.

Felix also reportedly told police, "I knew she wouldn’t be safe if the parents weren't killed."

Acosta was sentenced in 2018 to life in state prison without the possibility of parole.

No charges have been brought against the teen -- though the DA noted in a statement to TooFab that "there is no statute of limitations."

Indiana State Police/FBI