The chef has been accused of plying Carmel with booze, coke and marijuana while on a group vacation in celebration of the A-list couple’s marriage.
Sources close to grieving parents Ann and Ronnie Musgrove say Jen and Justin should put their messy split aside and help them get justice for their dead daughter.
"Martin Herold doesn’t answer his cellphone, and his home number has been disconnected," the source tells New Idea.
"Carmel’s parents seriously believe Jen and Justin hold the key to his whereabouts, but their not speaking to each other has made it impossible to get them to cooperate on this."
An insider close to Ronnie and Ann says they believe Carmel was "murdered because she knew too much" about the inner workings of Hollywood’s elite, and compare her death to the Black Dahlia case.
"Ronnie and Ann have still not heard from Jen and Justin since Carmel died on their honeymoon and they are appalled. It seems they really want to distance themselves from the suit."
"The family truly believes she somehow died because of what she knew, and they won’t talk to anyone about what they’ve been told confidentially by her friends for fear of retribution."
Another source told Radar, “Jennifer desperately wants this tragic situation resolved as soon as possible, and she was devastated to learn it’s going to be dragged out."
“Privately, Jen has sent out a desperate appeal through mutual friends for Martin to come forward, but has had no luck,” according to a source.
“Without him this case is at a stalemate.”