The U.S. Secret Service is investigating how a man entered the home of President Joe Biden’s national security adviser roughly two weeks ago without being detected by agents guarding his house, the Washington Post reported. An unknown man walked into Jake Sullivan’s home at about 3 a.m. one day in late April, and Sullivan confronted the individual and instructed him to leave, the report said, citing people briefed on the incident. Sullivan has round-the-clock Secret Service detail, but agents stationed outside his house were unaware that an intruder had gotten inside the home, according to the report.