As firefighters made their way to battle the blaze, the police said, the man who set the fire made his way to a barbershop in the heart of the village and shot four people with a shotgun, killing two customers and critically wounding two others.

He then drove a mile to a carwash in neighboring Herkimer and shot and killed two more people, the police said, before fleeing and setting off a manhunt.

The police discovered the suspect's car near a building on Main Street here around 1 p.m., but as they converged on the site, the suspect opened fire, sending officers diving for cover and setting the stage for a tense standoff that remained unresolved as of early evening.

Businesses were evacuated, schools placed on lockdown and, as heavily armed officers positioned themselves near the building — weapons drawn — the police said they were engaged in a "methodical" search for the suspect in and around the building and the surrounding area.

At 11:30 p.m., a spokesman for the Herkimer police said the suspect was still believed to be barricaded in the building on Main Street.

Gov. Andrew M. Cuomo, accompanied by the State Police superintendent, Joseph D'Amico, rushed to Herkimer, arriving shortly after the police were fired upon and spent several hours with the authorities near the site of the standoff.

"This is truly an inexplicable situation," Mr. Cuomo said in a news conference. "There was no apparent rational motive to the best of our knowledge."

The suspect was identified as Kurt Myers, 64, a Mohawk resident who had only one previous arrest, for drunken driving in 1973, the authorities said.

The State Police identified the dead at the barbershop as Harry M. Montgomery, 68, and Michael G. Rancier, 57, and at the carwash as Thomas Stefka and Michael L. Renshaw, whose ages were not immediately available.

As the sun faded over the Mohawk Valley, law enforcement officers with K9 units continued to search buildings in the area as an armored vehicle was brought to the scene, and officials from the Department of Homeland Security and the Bureau of Alcohol, Tobacco, Firearms and Explosives joined state and local law enforcement officials.

While officials said they evacuated most of those in the area, some residents remained trapped in their apartments.

Pat Roberts, 47, said his girlfriend, Christina Bruce, 27, was hiding in her apartment on Main Street with her 4-year-old boy, unable to leave and with little idea of what was happening outside. "She is nervous and scared," he said.

The police released a photo of Mr. Myers, who was seen frequently around town. Neighbors said he usually kept to himself and often acted strangely when he did interact with others.

Superintendent D'Amico said Mr. Myers set fire to his apartment at about 9:30 a.m. before driving the short distance to John's Barbershop at 17 Main Street.

He exchanged brief words with the people in the shop and then, seemingly unprovoked, began shooting with the shotgun, Mr. D'Amico said.

The two people killed at the shop were customers, he said, and "died at the scene."

The other two victims, including John Seymour, the shop owner, were taken to the hospital. Mr. Seymour was in fair condition on Wednesday evening at St. Elizabeth Medical Center in Utica.

Mr. Myers then got into his car and drove to Gaffey's carwash at 318 Mohawk Street in Herkimer, about a mile away.

As word of the shooting spread, there was confusion across the small, tightknit communities as dozens of police vehicles and ambulances raced between the two shooting sites.

Greg Beasley, 70, who was near the carwash when the shooting began, said he heard at least five gunshots around 10 a.m.

"I saw people running out from the one store building in panic," Mr. Beasley said when reached by phone, adding that he knew some of the workers there.

Vinny Ceneviva, 44, who owns Paesano's Pizzeria just down the street from the barbershop, said he watched as the victims were brought out, including Mr. Seymour. Mr. Ceneviva said Mr. Seymour was injured but alert when he was taken away in an ambulance.

"I have been here for 20 years, and John Seymour had his shop for 22 years," he said, adding that he would visit him regularly and that "he was a good friend of mine."

Mr. Myers has lived in the apartment he set on fire since at least 2005, according to property records. Neighbors said he had lived in the area for many years.

Traci Randall lived next door to Mr. Myers for four years but could recall only one conversation with him, and it did not go well. She said he accused her 12-year-old son of shooting a pellet gun at his car and screamed at him.

"I am thankful now that he never bothered with me and my family," Ms. Randall said.

Jamie Larson reported from Herkimer, N.Y., and Marc Santora from New York. Reporting was contributed by Priyanka Borpujari, Elizabeth A. Harris, Patrick McGeehan and William K. Rashbaum from New York, and Dennis Gaffney from Mohawk, N.Y.

This article has been revised to reflect the following correction:

Correction: March 13, 2013

An earlier version of two picture captions with this article misspelled the surname of the suspect being sought in the fatal shootings of four people in upstate New York. He is Kurt Myers, not Meyers.