SEATTLE (AP) -- Federal authorities said Wednesday they have opened an investigation into the failure of Washington Mutual Inc., the nation's largest bank failure.

"Due to the intense public interest in the failure of Washington Mutual, I want to assure our community that federal law enforcement is examining activities at the bank to determine if any federal laws were violated," Seattle U.S. Attorney Jeff Sullivan said in a written statement.

Sullivan said the FBI, the Federal Deposit Insurance Corporation's inspector general, the IRS, and the Securities and Exchange Commission have contributed agents to a task force looking into the matter. He asked anyone with information to contact authorities through a telephone tip line, or to e-mail the FBI's Seattle office.

Seattle-based WaMu ran into trouble giving loans to people with bad credit during the housing boom. As talk of the 119-year-old thrift's instability spread and its credit was downgraded, people began pulling their money out — leaving WaMu without enough cash to meet its obligations.

It was sold last month in a $1.9 billion fire sale to JPMorgan Chase & Co. and filed for Chapter 11 bankruptcy protection.

Sullivan's statement did not say what laws investigators believe may have been broken. His spokeswoman, Emily Langlie, said the U.S. attorney's office would have no further comment.

Sullivan asked anyone with information to contact authorities through their toll-free tip line of 1-(866)-915-8299, or to e-mail the FBI's Seattle office at fbise@leo.gov.