California voters rejected the latest attempt to repeal California's death penalty, dealing a blow to activists who saw this election as their best chance in 35 years to end capital punishment in the state.

Officials were still counting ballots, but it was apparent Wednesday that voters had rejected Proposition 34 by a margin of 52 percent to 48 percent.

The defeat came even though recent polling showed concern growing over the cost of capital punishment and its paltry results in California.

California has executed just 13 convicts and its death row has ballooned to 726 inmates since 71 percentage of the electorate voted to reinstate capital punishment in 1978. No executions have taken place since 2006 because of federal and state lawsuits filed by death row inmates.

The Legislative Analyst has said ending the death penalty would save the state $130 million annually.

Still, a majority of California voters still support the punishment in California.

"The people of California sent a clear message that the death penalty should still be implemented for those who commit the most heinous and unthinkable crimes," said McGregor Scott, the former U.S. attorney for Sacramento who served as the opposition's co-chairman.

Proposition 34 would have repealed capital punishment in California and shuttered death row, converting the death sentences of 726 inmates to life without the possibility of parole. The measure also would have created a $100 million fund to help investigate unsolved murder and rape cases.

The measure's backers, including the American Civil Liberties Union, vowed to continue fighting to end the death penalty in California.

"The mere fact that the state is evenly divided is nothing short of extraordinary," said Jeanne Woodford, a former warden of San Quentin Prison, where death row is located.

Woodford worked for the Proposition 34 campaign and is now an anti-death penalty crusader.

Supporters had pointed to an influential study published by a federal appeals court judge and law professor that concluded California has spent $4 billion to carry out just 13 executions and cover other death penalty costs since capital punishment was reinstated in 1978.

But many influential law enforcement officials and three former governors opposed the ballot measure. They argued that the condemned inmates would escape justice and that there were no true cost savings from closing death row.

The measure's backers vastly outspent opponents $6.5 million to $1 million. Billionaires Nicholas Pritzker and Charles Feeney, through his philanthropic fund, each donated $1 million. The American Civil Liberties Union contributed more than $700,000 and ran the campaign.

Federal and state judges have halted executions in the state since 2006 after ordering prison officials to develop new lethal injection procedures. Those lawsuits are still being litigated.