"I felt like a cheap whore," said Vincent Burroughs. In August 2011, at 9 p.m. on a warm night in Eugene, Ore., Vincent Burroughs said, he opened his front door to Dora Abrahamson. She was an IRS agent. She was auditing him. The two had never met. "She said she was going to do my paperwork," Burroughs said in an interview with ABC News. "She came up the stairs, knocked on the door. I opened the door." They went into his bedroom and had sex, Burroughs said. Watch the full story on "20/20: SHAMELESS?" TONIGHT at 10 ET.