A reader reports:

“Didn’t witness it first hand but when I boarded the train at Mt Vernon going to Chinatown and a man walked off with a skull mask out the door I entered. When I got in the car everyone had scattered to the ends and there were knife marks on the train car doors. An individual got a picture and reported in to police. It was around 9 AM.”

Updated report from another reader:

“Also it wasn’t a traditional skull mask. I thought it was a lizard mask (which is somehow scarier). It was definitely tan/yellow and not like a friendly cartoony skull.

When he got the knife out he said “I am going to kill the next person who touches me” and everyone near him crowded to the exit toward the back of the car near where I was sitting. I’ve never seen people react that way on Metro before. He said “oh now you’re all scared?” And followed the group to the back of the car. A man sitting in the wheelchair in the aisle stopped the knife/mask guy from coming any closer. I can’t imagine how scared the poor man in the wheelchair was. He got off our car at Mt Vernon Sq right after.”

Also curious – because I’ve never seen a message like this from WMATA before:

“Green Line Delay: Trains are holding in both directions at the request of the US Secret Service due to the Presidential Motorcade. Delays possible.”