Sentenced: Murderer Who Spent 4 Decades In Prison For Drowning Girl, 13, Is Arrested For Child Porn Possession

[Sugar Cookie]

A California murderer who spent four decades in prison for beating and then drowning a 13-year-old girl is back behind bars after allegedly being caught with disturbing child pornography, according to officials.

Marvin Lee Mutch, 68, was released in 2016 after spending 40 years in San Quentin Prison for murdering Cassie Riley in 1974, later becoming the subject of a documentary, “The Trials of Marvin Mutch.”


Mutch was just 18 at the time of the murder — and out on bail awaiting trial for allegedly kidnapping another 13-year-old girl at knifepoint when he drowned Riley.

He was taken into custody in Vallejo last Thursday for possession of child sexual abuse material, booking data from the Solano County Sheriff’s Office shows.

The murderer — who has always maintained his innocence — was serving as a director of advocacy for the Prisoner Reentry Network when he was re-arrested.

Several electronic devices were also seized for “forensic examination,” the sheriff’s office said.

Mutch is being held on a $300,000 bail and faces charges of possession of child pornography, being a convicted felon in possession of a firearm, being a convicted felon in possession of ammunition and possession of a controlled substance while armed.

The body of 13-year-old Cassie Riley was discovered in September 1974 in a creek bed close to her home. She had been beaten and held underwater until she died, prosecutors said at the time.

He spent the next 40 years in San Quentin Prison after being repeatedly denied parole, eventually securing his release in 2016.

Mutch’s Prisoner Reentry Network rushed to his defense after his latest arrest last week, claiming he is facing “persecution.”


Mutch “has been accused of crimes he did not commit,” the group insisted in a statement shared on Sunday along with an online fundraiser to pay for the convicted child-murderer’s legal costs.

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Murderer who spent 4 decades in prison for drowning girl, 13, is arrested for alleged child porn possession

In 1975, a jury took just five days to find Mutch guilty of murder.

nypost.com

 

[Sugar Cookie]

October 9, 2026

A Vallejo man who became a well-known advocate after being granted parole for a child’s 1975 murder is headed back to prison, this time for possessing videos depicting child sexual abuse.

Marvin Mutch, 70, was sentenced to six and a half years in federal prison on Friday, months after he pleaded guilty to downloading child pornography and having a gun as a convicted felon. The guilty plea was a turnaround for Mutch, who had previously claimed that he was being framed by hackers and was just holding the gun for a friend.

Mutch served more than 40 years in state prison for the 1974 murder of Cassie Riley, a 13-year-old girl whose partially clothed body was found in a Union City creek. The Alameda County District Attorney’s office argued that Mutch murdered Cassie because she rejected his sexual advances and fought him off during a rape attempt. He was convicted of murder in 1975.

In 2016, the year after he was paroled, Mutch was the subject of a KQED documentary that sought to highlight flaws in the parole system, including that Mutch’s long claims of innocence clashed with the commission’s general expectation for people to accept responsibility for their crimes.

In Mutch’s case, he claimed in 1998 to have been part of a Ku Klux Klan group and said he and two other boys drowned Cassie accidentally while attempting to force her to reveal the name of a Black boyfriend, so that they could get revenge on her for interracial dating. He said that on the advice of an unnamed adult, he brought her body to the creek and staged the scene to make it look like some sort of sex crime had taken place.

Later, Mutch claimed he’d made the whole thing up, and that he only did so because he believed he’d never get paroled if he didn’t offer some sort of confession. He filed several legal petitions from prison, seeking to overturn then-Gov. Arnold Schwarzenegger’s decision to reverse a 2006 grant of parole. In subsequent appearances before the parole board, he maintained he was innocent and that the crime against Cassie was horrifying.

He repeated his claims of innocence years later, as a free man, after becoming an advocate for prison and criminal justice reform.

But in 2025, Mutch was arrested on new charges involving sex abuse and children. The Solano County Sheriff raided his Vallejo trailer and arrested him on suspicion of possessing child pornography. Federal prosecutors say the “thousands” of files included, “depictions of children being sexually exploited, including images containing extremely young victims and qualifying as sadomasochistic.”

Marvin Mutch sentenced for having child sex abuse files after release from Union City murder sentence

Marvin Mutch once claimed he was part of a Ku Klux Klan youth group that was responsible for the murder of Cassie Riley, but then recanted and went back to maintaining his innocence.

www.mercurynews.com

 

[BuffettGirl]

Oh FFS! Dude you did it then, and you did it now (which he finally admitted at least). You killed Cassie because you couldn't conquer and abuse Cassie. You did it now because you're still a disgusting pedophile. The same reasons, separated by 50 years. Why are they ever going to let him out? He can't seem to help himself. I say we protect the COMMUNITY, and keep him behind bars for the rest of his pointless miserable life. Maybe I'm being unforgiving though?