New Orleans residents were baffled by a mysterious light which appeared inside Charity Hospital on Sunday. The kicker: Charity Hospital had been shut down and abandoned for more than 10 years. Photos show the hospital completely devoid of life and light, except for a ghostly glow in one of its central windows.

A nurse, working across the street from the hospital, posted the pictures to Facebook after she saw them on Sunday.

Another Facebook user, Mike Arbon, posted: "I work across the street from the old charity hospital [sic] and when I went up to the roof of the garage, in the middle of the dark building is this small bright Christmas tree that was put in the window. It's really pretty and little creepy. It gave me chills when I saw it and of course made me think of my brother, who passed away at charity hospital [sic]. But a very nice sight to see in the window of a dark building," according to Fox 8. When Headlines and Global News attempted to verify the post, the post had been removed from Facebook.

When university police investigated, they found out the eerie glow was not a Christmas tree, but some two-by-fours wrapped in lights, according to WWL-TV. It still remains unclear who placed them there, but police are treating it as a break-in.

An urban explorer claims to have done his own investigation, according to the Huffington Post, and has shared a photo showing a cardboard structure accompanied by lights.

A photo posted by Simi (@theshortestsim) on Dec 28, 2015 at 9:54pm PST

"Edit: someone is taking credit for sneaking in and putting a tree in this room, can't personally confirm. . A photo of the outside of this room is going viral and people think these lights are a ghost Christmas tree," read the caption. "The only thing scary about this is how much the City of NOLA spends to keep the power on." 

Charity Hospital closed down in the aftermath of Hurricane Katrina in 2005, but there is a campaign going to have it reopened.