Stonewalling by the Department of Veterans Affairs over its lavish spending on a pair of training conferences in Orlando, Fla., triggered a subpoena Tuesday from the House Committee on Oversight and Government Reform.

VA spent at least $6.1 million on the conferences in the summer of 2011, including as much as $762,000 that was squandered on such things as a $50,000 video parody of the movie "Patton" and $72,000 for snacks.

Committee Chairman Darrell Issa, R-Calif., said he was personally assured by VA Secretary Eric Shinseki that the agency would cooperate with the congressional investigation into the conferences.

Yet, agency officials have failed to deliver documents the committee has been seeking since August.

"It is unacceptable that Veterans Affairs still has not cooperated with the Committee's requests nearly a year after they were originally sent," Issa said in a statement late Tuesday.

"After the personal assurances I received from Secretary Shinseki and the accommodations made by congressional investigators, there can be no excuse for the continued delay," Issa said.

"I am forced to use the compulsory process and am determined to find out just why and how taxpayer dollars were spent in such an indulgent and careless manner," he said.

The subpoena seeks all communications related to the conferences from 13 department officials, including Shinseki.

Aside from failing to deliver the documents, VA officials have rarely returned phone calls from congressional investigators, according to a committee news release.

Committee staff called and emailed the department 45 times, and most of those communications went unanswered.

Yet despite repeated promises from VA that the documents would be delivered, and multiple deadline extensions from the committee, VA has failed to fully respond to requests for information.

The VA inspector general issued a report in October faulting the agency for excessive spending on the conferences. Some VA officials who helped plan the conferences accepted improper gratuities including free rooms and helicopter rides.

The IG found accounting and spending controls were so lax that it was unable to determine the exact cost of the events.

John Sepulveda, then the department's assistant secretary for human resources and administration, resigned the day before the IG report was made public.

Issa's committee has been investigating improper conference spending for more than a year. In April 2012, the committee sent letters to 23 agencies, including VA, seeking detailed records of conference costs.

In an Aug. 12 letter to Shinseki, Issa specifically requested emails and other documents related to the Orlando conferences, as well as the names and titles of everyone who participated in planning the events.

A VA spokeswoman did not respond to requests for comment.