One of the killers in the Bolsa restaurant murders has admitted his guilt and agreed to testify against his accomplices.

Michael Roberto has admitted his involvement in the gang shooting which took place on New Year's Day 2009 and left three people, including one innocent bystander, dead.

Roberto and Nathan Zuccherato were convicted of three counts of first-degree murder in the Bolsa case, but in June, a new trial was ordered after Roberto confessed to the murders.

Roberto contacted Calgary police to say that he was no longer affiliated with the gang and would like to become a witness.

In exchange for partial immunity, Roberto will now help the prosecution. As part of the agreement, Roberto will face a lesser charge and will get credit for time served in jail.

Roberto will be eligible for parole in as little as two years and seven months.