WASHINGTON — A lawmaker leading a congressional inquiry into the Secret Service raised questions Thursday about a White House volunteer’s possible involvement in a prostitution scandal that rocked the agency two years ago.

Rep. Jason Chaffetz, chairman of the House Oversight and Government Reform subcommittee on national security, said the White House had questions to answer in light of information he has received from Secret Service whistle-blowers, as well as a report in Thursday’s Washington Post.

Based on conversations with the whistle-blowers, Chaffetz, R-Utah, suggested the White House might be covering up information.

White House officials were adamant in denying involvement by anyone on their team in the incident. The scandal led to the firing of several Secret Service agents who had hired prostitutes while sent to Colombia with President Barack Obama for a 2012 summit.