John D. Sturgeon knew something was desperately wrong as he looked into the sky outside his Memorial Drive office building yesterday morning.

Before his eyes, a State Police helicopter, locked in a tailspin, lurched to one side and smashed onto the roof of the two-story Harvard Yacht Club building, killing the two state police officers and two American Telephone and Telegraph (AT&T) employees on board.

"It circled over, then it turned sideways and just came straight down," Sturgeon said. "It didn't explode--it was going straight down, and there was about a second, and then a big thud."

"It looked to me as if [the pilot] was trying to hit the water," Sturgeon said.

Eight members of the MIT Emergency Response Group were drinking coffee in the lobby of a building across the street when they looked out the window to catch the last few seconds of the helicopter's descent.

Utilities Construction Coordinator David M. Barber said the main rotor was motionless as the helicopter fell. His account essentially agreed with Sturgeon's: "The only thing running was its tail section...It made almost a 180-degree spin. It spun around relatively quick."

Barber said the tail of the aircraft slammed into the building first, pulling the entire craft down onto the tiny boathouse.

The MIT emergency crew's members, who are trained to rescue people from confined spaces but not from helicopter crash scenes, immediately rushed out to the sailing center.

"There was no time to get equipment," Barber said. "We just acted as best we could at the spot."

In a rush to reach the victims, the crew brokethrough a door leading to the center's preliminarycatwalk, Barber said.

The wreckage was strewn on the roof above them,and the crew had no way of climbing up.

They knocked on the center's door, but no onewas inside--the building was closed and not inuse, according to Barber.

The crew kicked down the building's door andfrantically searched inside for a way to reach theroof, he said.

They found a six-foot step ladder in thebuilding and brought it outside, Barber said.

But the ladder was too short, so four crewmembers including the emergency medical techniciancrawled the remaining distance on other crewmembers' hands and shoulders.

"We did everything we could to get up there,"Barber said. "Time was of the essence."