NBC DFW has learned more about a man killed by police in a standoff in the Medical District last week. Dallas police sources say that the man worked as security for Congresswoman Jasmine Crockett’s campaign for U.S. Senate.

Dallas police held a press conference about the incident on Monday.

Last Wednesday night, police followed 39-year-old Diamon Robinson into a hospital parking lot. The man had active warrants for impersonating a police officer and for stolen license plates. He barricaded himself in his car until police used tear gas to convince him to come out. Police then say he pulled a weapon, and they shot and killed the man.

Dallas police sources tell NBC DFW that Robinson also went by the name of “Mike King” and worked as a security guard for Congresswoman Jasmine Crockett during her campaign for U.S. Senate earlier this year.

Staff for Crockett’s campaign told NBC DFW they are waiting to comment after police release more details at the press conference.

According to campaign finance documents filed with the Federal Election Commission, there is a small payment of $340 for security services to a man named Mike King from last year. The deadline has not passed to file the latest paperwork for the March primary election.