Sydney Wilson, 33, a commercial real estate manager in the DC area, was visited by an officer for a welfare check at her apartment in Reston on September 16 at 10 a.m.
Officer Peter Liu - who had 14 years of experience in crisis intervention - knocked on the door, and Wilson opened.
When the officer identified himself, she slammed it back shut.
For the next three minutes, the policeman continued to knock, only for the 6ft 6in Wilson to open the door and charge him with a knife.