According to legal documents obtained by PEOPLE, Richards claims Sheen, 50, asked her and her children to move into a home next to him he had purchased, promising they would not be evicted should they do so.
Richards, 44, says she reluctantly agreed to move into the home in Mulholland Estates in Beverly Hills, California. After the move, Richards claims Sheen became more erratic in his behavior toward her and daughters Sam, 11, and Lola, 10.
In September, Sheen allegedly evicted Richards and her children and has not provided money for them to purchase a new home as his ex claims he had promised to do.
Sheen's lawyer says the lawsuit is about "nothing more than money, money, money."
"Denise Richards is not satisfied that she has received $660,000 tax free each year for almost 10 years," Sheen's attorney Martin Singer tells PEOPLE in a statement. "It is not enough money for her, besides the approximate $10 million she has received from Charlie under her short marriage."
But Richards shot back Friday morning on Twitter, writing, "Marty Singer u being the trustee should support a mom fighting to keep it intact for the children. It's their money, not mine or your client."
"Mr. Singer according to your calculations your client owes me an enormous balance," she added. "Wow thank u!"
Marty Singer u being the trustee should support a mom fighting to keep it intact for the children. It's their money, not mine or your client— Denise Richards (@DENISE_RICHARDS) January 22, 2016
Mr. Singer according to your calculations your client owes me an enormous balance. Wow thank u!— Denise Richards (@DENISE_RICHARDS) January 22, 2016
According to Sheen's attorney, Richards has been receiving $55k a month in child support payments over the past nine years. This is similar to what the actor has paid ex-wife Brooke Mueller under a settlement reached in 2010, which stipulated the actor would pay $757,000 plus another $1.2 million from the equity in their house. He also would provide $55,000 a month in child support payments.
In the lawsuit, Richards also claims to have overheard a conversation in which Sheen told their daughter Lola, "I'm going to kill you and I'm going to kill your mom."
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Sheen's attorney says those texts were intended for Richards, not their daughter.
"The texts were to Denise," Singer says. "It is very sad that she uses the children to get more money from Charlie and makes it almost impossible for Charlie to see his daughters."
Richards is seeking $1.2 million toward a new home, a sum she says Sheen previously promised to pay under the terms of a trust for their children.
Richards and Sheen became involved after she appeared in his show Spin City in 2001, and they were married the following year. Richards filed for divorce in 2005 while pregnant with Lola.
Richards later adopted a third daughter, Eloise. And for a time in 2013, Richards cared for Sheen's twin sons Bob and Max, whom he shares with Mueller, when Mueller sought help for her drug problems.
In November, Sheen revealed he has been battling HIV after being diagnosed in 2011.
A source told PEOPLE at the time that Richards has known about Sheen's HIV for "a number of years" but that neither she nor their daughters have tested positive.
In June, Sheen posted a series of now-deleted tweets about Richards, including one that read, "Denise Richards is a shake down piece of s--- doosh phace & worse mom alive. A despicable charlatan who sux ISIs ass."