Born in St. Louis, Missouri in 1943, Beardslee was the oldest of three children whose father died when he was 11. He was sent to a military school at age 15 and joined the U.S. Air Force at 19, where he served for four years as an aircraft mechanic. He and another airman were caught trying to steal a vehicle in 1965. He was sentenced to a work farm in Minnesota where he was hit by a falling tree and suffered a head fracture and a days-long coma.  He was married to Karen Kelly from 1966 to 1968.  In 1969 in Missouri, he choked, stabbed and drowned Laura Griffin, whom he had just met. They met in a bar; he went home with her and killed her. Beardslee turned himself in and confessed to the killing. He was convicted and served seven years before being released on parole. No motive was established nor did he offer any explanation.  Four years after leaving prison, he was arrested in California for the April 25, 1981 drug-related homicide of 19-year-old Patty Geddling and 23-year-old Stacie Benjamin in Redwood City, California. Prosecutors claim that a drug deal between the friends of Beardslee’s roommate had gone wrong. His roommate, Rickie Soria, lured the two to their apartment. The prosecutors noted that Beardslee sent Soria out to get duct tape to bind the victims before they arrived. Beardslee and, according to the prosecution, Bill Forrester, both shot Geddling, and later Beardslee slashed Benjamin’s throat after Cleo Frank Rutherford had tried to strangle her.

Beardslee’s phone number was found near Geddling’s body and when police called he confessed and led them to Benjamin’s body. At the time of this offence, he was still on parole for the 1969 Missouri killing which made him eligible for the death penalty as a repeat offender. Rutherford was sentenced to life in prison and died there in 2003. Soria pleaded guilty to second-degree murder and was still in prison in 2005. Bill Forrester was acquitted of charges in the case and charges against a fourth person were dropped before trial. Beardslee was convicted of first-degree murder and sentenced to death.  The defense tried to appeal on the grounds of inadequate defense since the original lawyer quit the case, and on grounds of mental defect due to a head injury from a falling tree in the Minnesota work farm accident when he was 21. Prosecutors noted that he was of above average intelligence although family members testified he had lifelong trouble expressing emotion and prison records indicate diagnoses of schizophrenia.  He was executed on January 19, 2005. Beardslee was the first prisoner to be executed in California since Governor Arnold Schwarzenegger took office. Schwarzenegger denied clemency to Beardslee, stating that “we are not dealing here with a man who is so generally affected by his impairment that he cannot tell the difference between right and wrong.”