Authorities believe 64-year-old Kurt R. Myers of Mohawk was behind the shootings. Guns and ammunition were found inside his apartment after emergency crews were sent to a fire there around 9:30 a.m.
Shortly after, they say he used a shotgun shot to shoot four people, two fatally, at a barbershop around the corner before killing two more at a Herkimer oil change and car wash business.
According to the Utica Observer-Dispatch, police believe the gunman is still in the area on foot, but other reports suggest he may have been picked up by a taxi.
About 1:30 p.m., a flurry of gunfire was heard near where police had narrowed their search.
A heavily armed police force bunkered down around an abandoned building, police and family members said.
Police officers were fired on from the building, which used to house a bar, on Wednesday afternoon while looking for Myers, state police Superintendent Joseph D'Amico said. At least one officer returned fire, and later it was unknown if Myers was still alive, D'Amico said.
Later, police spokesman Jack Keller said the troopers and local police would watch the building all night under the assumption that Myers was still alive.
The Associated Press contributed to this report.