Six months after the 32-year-old actress's death in December from pneumonia, anemia and multiple-drug intoxication, new allegations are surfacing about her controversial husband, the late British film producer Simon Monjack.
Murphy's former business manager Jeffrey Morgenroth tells PEOPLE that Monjack drained his deceased wife's cash reserves by 80 percent before his own death from anemia and pneumonia in May.
As a result, Murphy's mom Sharon, 57, is facing financial uncertainty, says Morgenroth.
"There were huge amounts of money in [Brittany's] pension plan and bank account, and all of that's gone," says Morgenroth. "I would see it on the statements. There was money being withdrawn by Simon, hundreds of thousands."
Even in the wake of Monjack's death, trouble followed. Jeannette Bycott, an assistant to Morgenroth, says she witnessed a scene in which Monjack's mother Linda ordered Sharon to leave the couple's Hollywood Hills house.
"Linda started acting like everything belongs to her," says Bycott. "Before Sharon could say anything, Linda stated the house was now hers."
Linda Monjack, who is grieving the loss of her son, denies any wrongdoing by either her or Simon, telling PEOPLE from her home in England, "If there is money missing I have no idea where it is."
Adds Linda, "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."
Fishy and WeirdBeyond the financial disputes, Morgenroth also echoes reports from many of Murphy's friends that Monjack maintained tight control over his wife.
He recalls one incident in which Brittany needed to sign a tax form. "I went down to the deadline and delivered it personally, and I couldn't even see Brittany," says Morgenroth, who alleges that Monjack also cut off his wife's cell phone. "Simon took [the form] from me. The excuse was her hair was messed up. I was at the front door and Brittany [called down] and said, 'Hi Jeff, sorry I couldn't see you, bye.' It sounded fishy and weird."
But for Sharon, who was extraordinarily close to her only daughter and son-in-law, such allegations are still hard to believe, says Morgenroth.
"She'll say, 'I can't talk about that now,' " says Morgenroth. "I'm trying to get her to understand that the bank account has this amount. She was looking at the pension statement and I said, 'Look. There are almost no zeros there.' She needs guidance on how to deal with things."
Reported by SARA HAMMEL and MONIQUE JESSEN