STATEN ISLAND, N.Y. -- If you've ever driven by Bayley Seton Hospital in Clifton and thought it belongs in a scary movie -- well, now it houses the criminally insane in a Batman spin-off series hitting TV in September.

After hearing a tip, a guard at the facility confirmed for us that cast from the show "Gotham" had been filming at the site this week, including a late night session that ended in the early-morning hours on Friday.

A giant, arching gateway at the facility was wrapped in tarp Friday afternoon, but photos posted online show that late Thursday night it read "Arkham Asylum" -- the infamous fictional facility that houses Batman's arch-enemies like the Joker, the Penguin and the Riddler in the comic book and movie series.

A Reddit article from a fan titled "I found Gotham's Arkham Asylum set near my house" has photos of how the hospital looked during filming.

We searched some more and came across a blog by author Christopher Begley titled Batman-News.com. On the site, an article titled "Exclusive: A first look at Arkham Asylum in 'Gotham' (photos)." Inside we found reader-submitted photos of Bayley Seton dressed up to play Arkham Asylum.

The article said that the crew was on set to film the first season's fourth episode titled "Lavender."

Here's a trailer for the show, which is set when Commissioner Gordon is a young police officer and Bruce Wayne just a boy and traces the rise of the unforgettable host of super-villains and vigilantes:

"Gotham" premieres Monday, Sept. 22 at 8 p.m. on FOX.

Bayley Seton Hospital is a psychiatric and social services outpatient hospital, operated jointly by Richmond University Medical Center and Saint Vincent's Catholic Medical Center. The buildings feature a mix of classic and modern architecture to give it the "spooky" element and is located in Clifton at 75 Vanderbilt Ave.