BERKELEY (BCN) — A California state senator showed her support for an end to state’s death penalty when she filed a legal brief late Friday on behalf of a man who had his death sentence overturned.

Sen. Loni Hancock, D-Berkeley, filed the brief with the United States Court of Appeals for the Ninth Circuit in San Francisco.

Federal District Court Judge Cormac Carney overturned a death sentence against Ernest Dewayne Jones last year and in the ruling declared the state’s death penalty unconstitutional. Hancock filed the brief, titled “Amicus Curiae” or Friend of the Court, in support of Judge Carney’s ruling.

“After reviewing many in-depth studies, I have come to the conclusion that California’s death penalty is not more effective in deterring crime than a sentence of life in prison without the possibility of parole,” Hancock said in a statement.

The senator said since 1978 California’s have spent $4 billion in tax revenue on the death penalty and she believes the money would have served residents better if it went toward reducing crime. Hancock said California could put an innocent person to death as has happened in other states. Attempts to speed up the system or reform it will only make errors more likely, Hancock’s office said.

State Sen. Mark Leno, D-San Francisco, and former assembly member Nancy Skinner, D-Berkeley, joined Hancock in filing the brief.