San Quentin- In a shocking murder attempt, Scott Peterson has been savagely beaten by fellow inmates at California’s notorious San Quentin State Prison, The ENQUIRER has learned exclusively.

The badly bloodied killer was rushed to the prison hospital, where he was stitched up – and then broke down in tears, reveal sources.

The 34-year-old fertilizer salesman – convicted of the brutal murders of his 8-months-pregnant wife Laci and unborn baby Conner – was ambushed on Sept. 21.

Guards were returning the handcuffed death row inmate to his cell when vengeance struck with a fury.

“Scott was literally beaten to a pulp while his hands were handcuffed behind his back,” revealed a source.