As emergency personnel used a heavy bulldozer to unload a mountain of rubble that used to be a four-story townhouse with a landmarked façade on East 62nd Street, tourists and New Yorkers alike pressed up against the blue police barricades to get a closer look yesterday.

What they saw was an “only-in-New-York” crime scene and the site of what investigators say appears to be the suicide attempt of a 66-year-old doctor, Nicholas Bartha, who was in the middle of a protracted divorce.

“I wanted to see the destruction in person because television doesn’t do it justice,” a businessman in town for two days from Akron, Ohio, Michael Widnor, said. “To see a four-story building just be changed in a matter of seconds to rubble is phenomenal.”

With the fires doused, investigators announced they had discovered that the gas line in the basement of the building had been tampered with, further bolstering suspicions that Mr. Bartha, the sole occupant of the townhouse’s twostory duplex on the top floors, had intentionally blown up the building.

“Anybody who’s handy can do this,” the chief fire marshal, Louis Garcia, said.

Not long before the explosion, Mr. Bartha allegedly sent a 15-page e-mail to his estranged wife, Cordula Hahn, where he made reference to ending his life.

Mr. Bartha survived the explosion and subsequent collapse, which happened at about 8:40 a.m.on Monday. He was pulled from the rubble with serious burns to his face and chest. A Parks Department employee, Jennifer Panicali, 22, was walking in front of the building at the time of the blast and was seriously injured. She was resting in stable condition yesterday.

The police commissioner, Raymond Kelly, yesterday said detectives weren’t able to interview Mr. Bartha yet because he was in an induced coma.

Even with the building destroyed, Ms. Hahn’s divorce settlement isn’t over, one of her lawyers, Polly Passonneau, said.

“Whatever we do from this point forward, we intend to do with delicacy, discretion, and respect for all effected by this event,” she said in an e-mail. “But as of this moment we do plan to go forward with the sale of the site.”

The vice president and CEO of the real estate appraisal firm Miller Samuel, Jonathan Miller, said Ms. Hahn won’t lose much financially because of the explosion.

“The part of property that appreciates is the land,” he said. “The only thing that is lost from a practical standpoint is the façade.”

A townhouse lot in the Upper East Side of comparable size is worth between about $7 million and $10 million, he said.