SOMERVILLE - A prosecutor under scrutiny for his office's investigation of the deaths of a powerful New Jersey couple is leaving office.

A spokesman for Gov. Chris Christie said that Somerset County Prosecutor Geoffrey Soriano will be replaced by Michael Robertson, a federal prosecutor.

Spokesman Brian Murray said in a statement, “Mr. Robertson is a seasoned attorney with over a dozen years of experience in private practice and as a prosecutor, including the last eight years as an assistant United States attorney. Robertson will begin in that position on March 7.”

A powerful group that includes three former New Jersey governors called on authorities to reopen the investigation into the deaths of John and Joyce Sheridan. Soriano's office determined that John Sheridan, former president and CEO of Cooper Health System, killed his wife and took his own life in September 2014.

The couple's four adult sons have accused the prosecutor of jumping to conclusions and are attempting to overturn the findings and have the case reopened.

The sons say that the evidence is not conclusive and they believed their parents were murdered by another person. A $250,000 reward is being offered to help find the killer.

A spokesperson for Prosecutor Soriano did not return News 12 New Jersey’s request for comment. Soriano’s term expired in October.

The Associated Press wire services contributed to this report.