Lawmakers say the Secret Service won’t let them hear from four employees who witnessed an episode outside the White House in which two high-ranking agency officials are accused of driving into a secure area without authorization.

On Sunday, leaders of the House Oversight Committee wrote to agency Director Joseph Clancy asking him again to let the four agents and officers testify at a hearing Tuesday about what happened March 4. They said Clancy agreed earlier only to testify as the agency’s sole witness.

The committee is trying to get to the bottom of allegations that two senior agents had been drinking when they drove into the area. The agents were accused of nudging a construction barrier with their vehicle as they intruded during an investigation of a suspicious item.

(AP)