As town police officers raced to Dr. William A. Petit Jr.'s home on Sorghum Mill Drive Monday morning they had no idea of the horrors that lay ahead.

By the time they reached the Deaconwood neighborhood of half-million-dollar homes, flames had blown out the rear of Petit's house. Two men were running away.

Inside the burning house, Petit, a prominent doctor and father of two who had been brutally beaten about his head and left tied up in the basement, hopped up the cellar stairs as the flames spread. He was the only one to make it out alive.

As he struggled, flames roared around his wife, Jennifer Hawke-Petit, a popular nurse at Cheshire Academy, who was unconscious and possibly already dead on the first floor.

The charred body of his oldest daughter, Hayley, 17, a recent graduate of Miss Porter's School in Farmington, was found at the top of the main stairs.

In a second-floor bedroom down the hall, the youngest in the family, Michaela, 11, was found tied to a bed. Her body was too badly burned to tell how she died.

The office of the chief state medical examiner will perform autopsies on the three victims today.

Police had been called to the house at 300 Sorghum Mill Drive about 9:20 a.m. on the report of a possible home invasion. Jennifer Hawke-Petit had been forced by the intruders to withdraw money from a nearby bank. While there, she somehow alerted bank employees -- possibly orally or by passing a teller a note -- and that brought the police.

As police were closing in on the neighborhood, the two men jumped in the family's Chrysler Pacifica SUV parked in the driveway.

The fleeing suspects rammed a police cruiser that tried to cut them off in front of the house and continued west on Sorghum toward a police roadblock about a block away.

Sgt. Chris Cote and Officer Tom Wright, both members of the department's SWAT team, had left their cars at the roadblock and were headed toward the house armed with semiautomatic rifles. Officer Jeff Sutherland was positioned at the roadblock.

Instead of slowing for the roadblock, the fleeing suspects gunned the SUV's engine and raced toward Sutherland. The SUV slammed into two police cruisers in the center of the roadblock. Their front ends mangled, the police cars spun apart from each other on impact. Sutherland escaped injury. The Pacifica, front end damaged and airbags deployed, rolled 30 feet before stopping against a neighbor's manicured lawn.

Officers, guns drawn, swarmed the vehicle and pulled the suspects out.

Police would not release the suspects' identities late Monday but sources close to the investigation said one was a 25-year-old Cheshire man. The other is about 40 and believed to be from the Naugatuck Valley.

Cheshire Police Chief Michael Cruess said the department was not releasing names or charges until the men are formally charged. The investigation is being led by detectives with the state police major crime squad.

The suspects are expected to appear in Superior Court in Meriden this morning. Police said they are treating the scene as a "home invasion-arson-homicide.''

Investigators found a car -- believed to belong to one of the suspects -- in the Quarry Village subdivision about 1 1/2 miles away.

On Monday, investigators had not determined what brought the men to the Petits' home.

William Petit was listed in serious but stable condition at St. Mary's Hospital in Waterbury Monday night.