A spokesman for the Metropolitan Transportation Authority said Sunday the organization and police are investigating after a video was posted online Wednesday featuring actors portraying zombies and scaring people by clawing at them through a subway grate in the city, the New York Post reported Monday.
The clip also shows the "zombies" preparing for the stunt by prying the grate open and climbing inside.
"We are deeply troubled by this video," the spokesman said.
He said marketing company Relevant did not have permission from city officials to stage the stunt, which was designed to promote AMC's zombie-themed series "The Walking Dead," which returned with new episodes this week.
Police said the incident is being investigated and could result in charges including trespassing, disorderly conduct and criminal mischief.
Relevant officials did not return calls for comment, the Post said.