The investigation will focus on whether paperwork was correctly processed Officials in 49 US states have started a joint investigation into whether mortgage firms were wrong to repossess hundreds of thousands of US homes.
It follows allegations that the companies often mishandled documents when people behind on their mortgages had their houses taken from them.
According to industry figures, more than 2.5 million US homes have been repossessed since December 2007.
On Tuesday the White House ruled out a temporary ban on home repossessions.
All states apart from Alabama have joined the joint investigation, as has the capital Washington DC.
It is not yet known why Alabama has chosen not to participate.
Officials will study the accuracy and legitimacy of the documents that lenders used to evict people from their properties.
It follows allegations that some bank employees signed off on repossession documents without reading them.
Iowa Attorney General Tom Miller said: “This is not simply about a glitch in paperwork.
“It’s also about some companies violating the law and many people losing their homes.”
Lenders including Bank of America and JP Morgan Chase have already halted questionable repossessions.
Others, such as Citigroup and Wells Fargo have not done so, saying they have done nothing wrong.
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