Department of Homeland Security officials are refusing to release immigration documents for ­Tamerlan and Dzhokhar Tsarnaev, citing the agency’s ongoing investigation into the Boston Marathon bombing allegedly carried out by the Chechen brothers.

Both the Boston Globe newspaper and nonprofit watchdog Judicial Watch have requested immigration records and other records related to the bombings through Freedom of Information Act requests.

James Holzer, a senior FOIA officer for DHS, told the Globe on Tuesday he witheld the records based on a law enforement exemption that shields information “compiled for law enforcement purposes, the release of which could reasonably be expected to interfere with enforcement proceedings.”

DHS  may also be using the exemption to conceal information that could embarrass the government over its handling of evidence about the brothers, ­Judicial Watch President Tom Fitton told The Washington Examiner. 

“This administration is less transparent than the Bush administration,” Fitton said.

Anyone who says otherwise hasn’t filed any FOIAs under this administration, he added.

Tamerlan, the older Tsarnaev brother, was a legal U.S. resident who could have been deported after a 2009 domestic violence arrest and conviction, as Judicial Watch reported in April. And Boston’s police commissioner said federal agents never told Boston police they inves­tigated Tsarnaev.

The law enforcement exemption is a matter of DHS discretion, Fitton said. But President Obama’s administration “drops a stone wall over any inquiry,” he added. “The idea that all of this should be walled of from scrutiny obviously shouldn’t be the case,” he said.