The VA on Monday released an internal audit that found more than 100,000 veterans were subjected to a wait of 90 days or more for healthcare appointments at medical facilities nationwide along with widespread instances of schemes to mask the delays to meet targets for bonus awards.
The issues first came to light at a facility in Phoenix. A Department of Justice spokesman said on Wednesday that the FBI had stepped in and that its work would help determine whether criminal activity had occurred.
"At the department's direction, the FBI has instructed agents in its Phoenix office to conduct an investigation into the allegations related to the VA," the spokesman said.
"Federal prosecutors will be working with these investigators to determine whether there is a basis for criminal charges," he said.
The FBI involvement is the latest escalation of a scandal that prompted the resignation on May 30 of Secretary of Veterans Affairs Eric Shinseki, a retired Army general wounded three times in Vietnam.
The announcement follows the release of the internal VA survey, which showed that the scandal over the cover-up of long wait times at VA clinics, during which some veterans are alleged to have died, was broader and deeper than initially thought.
The agency said staff at 76 percent of facilities surveyed reported that they were instructed to misrepresent appointment data at least once.
The VA said it found that in mid-May, 57,436 veterans were waiting for appointments that could not be scheduled within 90 days, while about 43,000 had appointments more than 90 days in the future.
The issue has dogged the White House in recent weeks and embarrassed Obama, who came into office promising to elevate care for U.S. veterans.
Since the crisis erupted, he has tasked his deputy chief of staff with helping to sort out the problems at the VA and named an acting secretary, Sloan Gibson, to take over for Shinseki.
The VA report made no mention of whether the long wait times had resulted in any deaths of veterans. Doctors at VA clinics in Phoenix have alleged that some 40 veterans died while waiting for care.