It was an abandoned building in the City of Middletown that officials say attracted a lot of trespassers. But on Sunday, the old psychiatric center went up in flames. Jessica Chen has more on what is next for the building. 

MIDDLETOWN, N.Y. -- More than 24 hours since this fire started in Middletown, crews are still battling it on Monday. 

"We surround the building with massive streams and eventually it'll go out," said 2nd assistant Fire Chief Nick Barber from Middletown.

He said it took a while for firefighters to put out the flames at the abandoned psychiatric center in Middletown, because the fire started in the middle of the building. At one point, more than 100 firefighters were onsite.

"It was tough because all the windows were boarded up, we had to get in there and get all the plywood off the windows, set up a bunch of lines and surround the building," said Barber.

Demolition crews knocked down part of the building Sunday night because the interior had already collapsed. Barber said the remaining building will also go down after the hotspots are put out. 

"If somebody was to walk by it and it collapsed, it would potentially kill them," said Barber.

He said it's still unclear who started the fire early Sunday morning. But in the past he said, squatters and trespassers have been a problem at the empty site.

Officials said the building is privately owned.

"It was uninhabitable and we don't want any vagrant and squatters going in there, so it has to come down, it's unsafe," said Barber.

And a day after the massive fire, crews are now cleaning up what's left of this former psychiatric building. 

The city of Middletown Police Department is handling the investigation.