David Fleetwood, a supervisor of Chestnuthill Township, died in a hospital about an hour after the shooting at the Ross Township municipal building, The Allentown Morning Call reported.
James V. LaGuardia, 64, and Gerard Knox, 53, both of Saylorsburg, died at the scene Monday night, the Monroe County coroner's office said.
Two other people were wounded. One was in serious condition after being flown to Lehigh Valley Hospital - Cedar Crest. The other suffered a grazing wound to the head, police said.
Initial reports placed casualties at four dead and six wounded.
State police said Rockne Warren Newell, 59, of Ross Township, near Allentown, first fired a long gun through the Ross Township municipal building windows during a town supervisors meeting about 7:20 p.m. local time
Fifteen to 18 members of the township's Supervisors Council and the public were at the meeting.
Newell then entered the building, still firing, before briefly leaving and returning with a handgun, police said.
The executive director of a park and open space commission "bear-hugged [Newell] and took him down. He shot [Newell] with his own gun," a witness told WCAU-TV, Philadelphia.
Another person helped tackle and restrain Newell until police arrived, witnesses said.
Newell was taken to a hospital and later released to police, who didn't immediately give a motive for the shooting.
The Pocono Record in Stroudsburg reported in June Newell was in a dispute with the township for 18 years over the condition of his property.
A Monroe County judge ordered him to vacate the property a year ago and he started living in his 1984 Pontiac Fiero and in abandoned buildings.
"They have no right to kick me off my property," Newell told the newspaper in June. "They call my property an 'eyesore.' When I bought it, it was one of only three properties on the entire road that didn't have what they call 'junk.'"