Ally Financial Inc. is facing another fraud lawsuit over allegedly defective mortgages linked to its bankrupt ResCap unit in Bloomington.

Boston-based John Hancock Life Insurance Co. is accusing Ally Financial and its affiliates and a range of other players, including major investment banks, of fraud and negligence in connection with about 50 residential mortgage-backed securities from 2003 to 2007, according to a lengthy complaint in U.S. District Court in Minnesota.

The 208-page complaint, filed Friday, doesn't allege a specific damage amount. It accuses the defendants of "wholesale and systematic abandonment of underwriting guidelines" in the rush to supply more loans to bundle and sell down the chain.

The lawsuit is one of scores alleging fraud that investors have filed in recent years as they attempt to hold parties accountable for the pools of home loans that were at the heart of the housing collapse.

Detroit-based Ally Financial, formerly known as GMAC, faces four such lawsuits in Minnesota courts because of its bankrupt ResCap unit, which was a major subprime mortgage player with brands such as Ditech, GMAC Mortgage and Homecomings Financial. Ally is about 70 percent owned by the U.S. government after a 2009 bailout.

Residential Capital LLC (ResCap), an Ally subsidiary, filed for Chapter 11 bankruptcy protection in May. ResCap was originally founded in Minnesota, but the workforce at its Bloomington base has dwindled to about 80 people.

Because of bankruptcy protection, ResCap is not a defendant in the latest lawsuit. However, a group of 11 former executives at ResCap and its affiliates are named as individual defendants. They include Bruce J. Paradis, former president and CEO of GMAC RFC and David C. Walker, a director of ResCap affiliates including Homecomings Financial.

"They clearly dispute the allegations and believe they acted entirely in good faith. Beyond that, I'm not going to comment," said James Langdon, a lawyer at Dorsey & Whitney representing the group of former executives.

Lawyers for John Hancock either declined to comment or didn't return phone calls.

Ally Financial issued a statement saying that it has "strong legal and factual defenses to the claims in the lawsuit."

"Further, the claims relate to the activities of ResCap, which has filed for Chapter 11 protection in bankruptcy, and are subject to resolution in connection with the ResCap bankruptcy," it said.

Ally Financial was one of the five financial institutions that agreed to pay $25 million earlier this year to settle allegations by the federal government and state attorneys general of mortgage loan servicing and foreclosure abuse.

Jennifer Bjorhus • 612-673-4683