NEW ROCHELLE, N.Y. (CBSNewYork) — There are new details about the suspicious fire that destroyed a historic Westchester County mansion on Monday afternoon.

New Rochelle officials said Tuesday that work crews were at the scene just hours before the blaze began, checking on whether the building was secure from trespassers, CBS2’s Tony Aiello reported.

The view from a drone shows the extent of the incredible damage — a 20-room mansion, gutted.

“This is, of course, a very sad day for New Rochelle. We have lost one of our community’s true historic architectural treasures, a structure that is beloved and has been beloved by generations of New Rochellians,” New Rochelle Mayor Noam Bramson said.

Watch: Officials Discuss Mansion Fire

Many who grew up attending events here said it hurts to see Wildcliff reduced to a burned-out shell.

When asked how she felt Tuesday, Patrice Havelka summed up the thoughts of many, “Upset. Sad. Annoyed.”

Havelka said she believes New Rochelle didn’t do enough to safeguard Wildcliff.

CBS2’s Aiello obtained pictures that show the Gothic revival mansion in 2009. It was built for a rich family in the 1850s and then donated to the city in the 1940s, where it was used for community events until it was shuttered a decade ago.

“It wasn’t put to good to use lately, but that’s the way things happen with abandoned buildings,” resident George Morris said. “People take advantage of it.”

“That should have been taken care of. That building should have been secured, and somebody … it had to be better well kept up,” resident James O’Toole said.

mansion Investigators Probing Suspicious New Rochelle Mansion Fire

An image from drone video shows the charred remains of the mansion in New Rochelle. (Photo: John Hessel/101010NR.com)

The fire is clearly considered suspicious. It burned hot and fast in a building with no gas or electric service.

Arson dogs worked the scene late into Tuesday afternoon.

City officials said over the years there have been concerns about kids or homeless people trespassing at Wildcliff, and just six hours before the fire, city crews were checking to make sure the doors and windows were properly boarded up.

“Just a report there were some openings that needed to be secured. I think it’s an unfortunate coincidence,” City Manager Charles Strome said.

Strome and Mayor Bramson said critics are wrong — securing the future of Wildcliff was a priority.

“Some years ago we sold the adjoining property, used the proceeds of that sale in order to reconstruct the roof and to secure the building,” Bramson said.

That reconstructed roof collapsed during the fire. The answer to how it started is somewhere in the rubble.

The mayor said recent efforts to find a tenant for Wildcliff always fell through. The city was on the verge of seeking another round of proposals, but that’s now on hold obviously due to the fire.