Vice President Joe Biden’s office stonewalled a Freedom of Information Act (FOIA) request for his travel expenses, according to Ronald Kessler’s new tell-all book on the Secret Service, The First Family Detail.

Kessler, a former Wall Street Journal and Washington Post investigative reporter, filed a FOIA request in April 2013 with the Air Force for the details and costs of Biden’s personal trips.

"But in what amounts to a cover-up on behalf of the vice president, on June 6, Biden’s office blocked transmitting the results to me and told Air Force officers they were not to comment to anyone about the case," Kessler writes.

According to Kessler, Biden’s then-deputy counsel Jessica Hertz took over the FOIA case from the Air Force and ordered it not to release the 95 pages of documents it had compiled in response to Kessler’s request.

"They are covering up," an Air Force officer told Kessler. "We spent a lot of time compiling the records, but Biden’s office said logs for each flight would have to be consulted. This is a smokescreen designed to delay providing any records as long as possible."

The records were eventually released to Kessler by an Air Force officer who "was outraged that Biden’s office would taint the Air Force by politicizing its FOIA process."

The records show Biden’s trips—which include multiple daily flights between Washington, D.C., and Wilmington, Delaware—cost taxpayers nearly $1 million between January 2009 and March 2013. This does not include crew costs or the cost of ferrying Biden between the vice president’s residence at the Naval Observatory and Andrews Air Force Base.

"Every three or four weeks when it’s warm, Biden gets up there on Saturday and then will fly back on Air Force Two," a Secret Service agent told Kessler. "While Air Force Two is sitting on the tarmac at Andrews, he goes up and plays golf with the president at Andrews Air Force Base, gets back on the plane, and flies back to Delaware. Let me tell you something, that is egregious."

An Air Force source also told Kessler that Biden regularly schedules single events in Arizona so he can fly there on the public dime to play golf.