A Metro passenger who was upset about delayed service was stabbed dead after he went inside a manager's booth at the Friendship Heights Metro station and hit a worker.
Jeremy Bond, 28, of Rockville, later died at a hospital, police said.
Officers were called to the station on Wisconsin Avenue NW at 12:21 a.m., nearly an hour after the station was scheduled to close.
Bond pounded on the windows of the manager's booth and then entered to complain about delayed service, police said.
An physical altercation ensued, and Bond hit the worker in the arm, police said.
The employee — fearing for their safety — stabbed the man in the chest with a pocket knife, according to a police report.
The employee may have a case for self-defense, D.C. police chief Peter Newsham said.
"If you have an employee who's working inside of a booth, somebody enters that booth and there's a physical altercation, there could be a viable self-defense claim," he said.
A housemate of Bond said he was stunned to hear what happened.
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"I never was fearful of him or anything," he said.
Court records show Bond was arrested in November after he busted out the windshield of a car that nearly hit him. He was charged with malicious destruction of property but the charges were dropped after he paid for repairs.
No charges have been filed against the worker.
Metro declined to provide information on whether employees are allowed to carry knives on the job.
Investigators have surveillance footage and some witnesses to talk with.
D.C. police dispatch initially said the man died from his injuries, but a D.C. police spokesperson later clarified he was in grave condition. Police announced on Tuesday night that the situation had become a death investigation.