A law firm said on Monday it had filed an investor lawsuit against Washington Mutual Inc, alleging it pressured a unit of First American Corp to inflate the appraisal value of homes.

The lawsuit comes after New York Attorney General Andrew Cuomo sued First American and its unit eAppraiseIT last week for allegedly colluding with Washington Mutual to inflate the appraisal values of homes. Cuomo did not name Washington Mutual as a defendant in his case.

The latest suit, which seeks to represent investors who bought Washington Mutual shares between July 19, 2006 and Oct. 31, 2007, also names certain officers and directors of the largest U.S. savings and loan, the law firm, Wolf Popper LLP, said in a statement.

Washington Mutual spokeswoman Libby Hutchinson said the company doesn't comment on the specifics of litigation.

But she added, "The integrity of our appraisal process is very important to us, and we work hard to make sure that it operates properly."

The suit, which was filed in U.S. District Court in New York, alleges claims for securities fraud, the law firm said.

The complaint alleges that inflated appraisals led to Washington Mutual's financial results to be misstated, it said.