The sweeping fire that ripped through the former Kenwood Convent and Doane Stuart School Friday night destroyed the Albany landmark and left elected officials feeling distressed and full of questions as an investigation into what started the blaze commenced.

Massive flames and billowing smoke from the 19th Century building on Southern Boulevard in Albany could be seen from miles away. The fire started just before 6:30 p.m. Thursday, and crews were still on hand Friday morning, working to control the site.

“We lost a treasure here and it’s challenging, it’s frustrating,” Mayor Kathy Sheehan said Friday.

The property dates back to the 1840s, and has a rich history.

Fire crews responded within 10 minutes of the first calls, according to Albany Fire Chief Joseph Gregory.

“The fire was throughout,” Gregory said. “Within minutes of our arrival, the steeple collapsed on the building. That shows you how well-involved the fire was at that point.”

Two dozen units responded. It took more than 50 firefighters about four hours to snuff out the blaze, which consumed the 100,000-square-foot building.

Doane Stuart occupied the property from 1975 until June 2009, when it moved to a campus in Rensselaer. The structure had been vacant since.

More recently, developers had hoped to turn it into a mixed-use development called Kenwood Commons. The building was put up for auction earlier this week. Sheehan said Friday she was unsure of the legal status of the property. But the redevelopment efforts over the years consistently stalled.

The former owner — Kenwood Commons LLC — owed $5.5 million in back taxes and had entered bankruptcy proceedings, according to officials.

“I have to tell you, we had a plan of action for here and as a kid growing up and running this property, seeing this beautiful building the way it looks today it’s a shame,” Albany County Executive Dan McCoy said.

It was unclear who presently owns the property, though a bid for it was made last Tuesday by a company called Guild Investment Management, officials said.

“I don’t know the legal status of what happens with that, but this building and property was auctioned in that bankruptcy,” Sheehan said.

Efforts to contact representatives for Kenwood Commons and the recent bidder were unsuccessful Friday.

Rick LaJoy, director of the city’s Department of Buildings and Regulatory Compliance, said, “We were called here over a dozen times for plywood being removed and people getting into the building and vandalizing and stripping materials.”

The fire at the property left former occupants shocked and sad due, in part, to its extensive history.

The former Doane Stuart School, better known as the Convent of the Sacred Heart in Kenwood, dates back to around 1842. It was built as a country estate for businessman Joel Rathbone and his family. Rathbone was the brother of Albany's first elected mayor, Jared, and uncle to Henry Rathbone, who was in the booth at Ford Theatre in Washington, D.C. with Abraham Lincoln at the time of his assassination.

Rathbone selected the spot for its seclusion and sweeping views of the Hudson River to the east and the Catskill Mountains to the south. He sold his home to the Sisters of the Sacred Heart in the early 1850s, and it was converted into a school.

Sacred Heart eventually tore down the original Rathbone estate and built a school and the convent using the original buildings materials, along with new bricks and mortar, some of which could be seen in the rubble on Friday.

The building expanded in the 1860s and several other times in the late 19th Century. By about 1900, the building, for the most part, was complete. In the early 1920's, a new front was added on, and in the 1930s and 1960s, new portions of the school were constructed on the east and west wings connected by bridges.

Both of those structures were mostly left unharmed.

In 1975, Sacred Heart merged with St. Agnes. The parochial schools were combined into Doane Stuart.

“It was a very active place, as you can imagine,” said Patricia Hodgkinson, who started a career as a teacher at Doane Stuart about 40 years ago. The address also marked the beginning of her relationship with her husband Seamus.

“We were married in 1986 in the chapel there, and our three children attended Doane Stuart,” Hodgkinson recalled. “They were all baptized in the chapel, so the place has such special memories for us.”

Hodgkinson said she’s begun organizing a memorial service for next month.

“That will bring many alum together — an opportunity for us to share all of our memories that we made within the walls of that building there were so, so many,” she said.