At least five US banks are being probed for overcharging foreclosure fees on federally backed mortgages. Reuters/Brian Snyder

At least five American banks are being investigated by Manhattan's US Attorney office to see if they overcharged the US government for expenses acquired during foreclosures on federally-backed mortgages.

According to records that were seen by Reuters, MetLife, Santander Holdings, PNC Financial Services, PHH Corp and Citizens Financial Group – Royal Bank of Scotland's US firm – have all received subpoenas.

The office of Preet Bharara, US Attorney, is looking at foreclosed loans which were insured by the Federal Housing Administration, guaranteed by the Federal National Mortgage Association, more commonly known as Fannie Mae, and mortgage regulator Freddie Mac.

The summons will be used to garner information about the banks' foreclosure expenses.

The investigation stems from the foreclosure crisis in 2010, which saw widespread improper mortgage foreclosures from large banks and other lenders.

"You've got a lot of people trying to clean up the servicing industry, but the truth is we are seeing the same servicing problems over and over. It was built into the model to charge as many fees as they could," Ira Rheingold, director of the National Association of Consumer Advocates, told Reuters.

Citizens Financial says that the examination is being carried out in accordance with the Financial Institutions Reform, Recovery and Enforcement Act (FIRREA).

FIRREA was a heavily influential act during one of the office of Bharara's previous investigation which looked at improper approval of Federal Housing Administration protected loans which resulted in a settlement worth $1.1bn (£657m, €808m) from JPMorgan, Deutsche Bank Ag, Citigroup, Flagstar Bancorp and Chase & Co.