WASHINGTON (AP) — The federal government on Tuesday threw its support behind a lawsuit against JPMorgan Chase accusing Bear Stearns, the investment bank JPMorgan bought in 2008, of engaging in massive fraud in deals involving billions in residential mortgage-backed securities.

At a news conference, acting Associate Attorney General Tony West credited a federal-state working group of law enforcement agencies created by President Barack Obama in 2009 with assembling evidence in the lawsuit brought by the New York attorney general’s office.