![Michael Spengler](https://d.hngn.com/en/full/292789/michael-spengler.jpg?w=736&f=c6e095fca5a47ec9b7311d4266780079)
A California man serving a life sentence for the "senseless" slayings of two friends was killed with a homemade weapon allegedly wielded by another lifer convicted of trying to murder his father.
The deadly attack took place in the Salinas Valley State Prison in Soledad, California, around 10:30 a.m. local time Monday, corrections officials said.
Prison staffers intervened and paramedics pronounced Michael Spengler, 38, dead about 40 minutes later.
No one else was hurt and alleged attacker Miguel Espino, 31, was placed in restricted housing pending the results of an investigation, officials said.
![Miguel Espino](https://d.hngn.com/en/full/292791/miguel-espino.jpg?w=736&f=20633d9f4cc9b0998bae004217e05a37)
A spokesperson for the California Department of Corrections and Rehabilitation said information about the weapon Espino allegedly used and a suspected motive wasn't available.
In November, jurors convicted Espino of first-degree attempted murder and related charges for setting fire to his father's mobile home after using a hammer to beat him unconscious inside, TV station KESQ reported at the time.
Arturo Espino Sr. survived the horrific 2018 incident in Desert Hot Springs, about 100 miles east of Los Angeles, when neighbors spotted smoke from the blaze and rescued him with the help of a fire extinguisher.
Spengler was convicted in 2022 for the fatal shooting of Michael Meza in Pomona and the deadly beating of Marcus Nieto in Altadena, radio station KFI reported when he was sentenced later that year.
The victims were killed about a month apart in 2013, with the judge in the case calling Spengler an "extremely dangerous man" who should "never be released from prison."
"Both murders appear to have been surprise ambushes of the defendant's friends," Superior Court Judge Henry J. Hall said during Spengler's sentencing. "They appear to be largely senseless."
While locked up and awaiting trial, Spengler -- who claimed innocence -- became a jailhouse lawyer who filed seven civil rights lawsuits over his alleged mistreatment in the Twin Towers Correctional Facility in Los Angeles, according to a court ruling posted on the Casetext website.