An ad agency may be in trouble for staging a zombie-themed stunt in New York City ahead of "The Walking Dead's" return to TV. Could the network get sued… or worse?

Here's what we know so far: Last week, the video above a video promoting AMC's "The Walking Dead" hit the Internet. The video documented a prank played on New Yorkers — average folk shrieking and fleeing as "zombie" hands suddenly reached for them through a sidewalk subway grate on 14th Street at Union Square.

The city's transport authority was not amused and has reached out its own claws toward the local cops for help. (Sorry. Not every zombie metaphor can be a great metaphor.)

[Related: Why Aren't Your 'Walking Dead' Favorites Bigger Hollywood Stars?]

H. Tony Berger, CEO and founder of Relevant, the New York ad agency that spearheaded the jape, has told the media that he believes the whole project was done on the up and up.

And just now, AMC has exclusively released a statement to Yahoo TV on the matter.

"AMC would never engage in this kind of stunt without the proper approvals," a spokeswoman told me this morning. "The agency hired to produce the video has assured us that all necessary notifications and authorizations were in place and that they were in contact with the NYPD."

The NYPD didn't return requests for comment. But defense attorney Stanley L. Friedman says that the prank could result in multiple charges.

"There's a whole series of potential misdemeanors and even felonies," Friedman tells me. "Disorderly conduct, breach of peace, public disturbance, trespass, criminal mischief. And if there's evidence for it, there could be a charge of conspiracy to commit a misdemeanor."

The most likely scenario? That the planners behind the jape would be the ones to take the legal hit, Friedman says.

"My experience is that, generally, they go after the organizers," Friedman says. "That's going to send more of a deterrent, even though the actors themselves should have known better. … Typically the prosecutors want to look at someone who made the money. "

I'll be updating you as this story shambles forward.

Got a Burning Question? Tweet it to us @YahooBurningQs.

Leslie Gornstein is an entertainment writer and the host of the weekly Hollywood gossip podcast The Fame Fatale.