Zackariah Timothy Lehnen, 30, was placed on unsupervised parole in November after serving less than five months of a 16-month prison sentence for drug possession.
Lehnen is now charged with the deadly stabbing and beating of a woman and an elderly man this month in Culver City and faces arraignment late this month.
The Legislature passed the law allowing what it termed "non-revocable parole" in 2009 as a way to save money by returning fewer lower-level offenders to prison for minor parole violations. The law took effect in January 2010.
More than 13,000 ex-convicts are currently in the program and are not being monitored.
State Sen. Ted Lieu (D-Torrance) criticized the computerized risk-assessment program the state Department of Corrections and Rehabilitation uses to decide when it is safe for parolees such as Lehnen to go unsupervised once they are released from prison.
He called the risk assessment "fatally flawed" in a letter sent this week to the corrections secretary.
"We are now seeing not just the potential public safety consequences, but actual consequences. More lives need not be lost," he wrote in the letter."
The Associated Press contributed to this report.