The Brit died in May (10) just five months after his Hollywood actress wife passed away..
Murphy's former business manager, Jeffrey Morgenroth, has waded into the tragedy by alleging Monjack drained his late wife's estate before his own death, claiming "huge amounts of money" had gone missing.
He told People.com, "There were huge amounts of money in (Murphy's) pension plan and bank account, and all of that's gone. I would see it on the statements. There was money being withdrawn by Simon, hundreds of thousands."
But Monjack's mother Linda is adamant her son did not squander his late spouse's cash.
She says, "If there is money missing I have no idea where it is. He didn't get much, maybe a few hundred dollars, and he paid off his debts with it. He was spending his time crying his eyes out most of the time. He was in a terrible state."