The gunman reportedly returned to the original location and wounded another relative before being shot and killed by deputies.
The shootings happened on Wednesday at several places along a rural road about 4 miles (6 km) from the center of town in Madison, according to Maine State Police.
The victims who were killed were Tuttle's wife, 52-year-old Lori Hayden, their 25-year-old son Dustin and 57-year-old neighbor Michael Spaulding.
Michael Spaulding's son told us that his father may have been killed in a jealous fit of rage.
McCausland said central to the investigation is Harvey Austin, who was wounded.
"He was the nicest man I've ever known", said Spaulding. "I have no clue; he never would tell me anything negative about anyone".More news: Mavs, Nowitzki agree on 2-year, $10 million deal
ME state police say they don't know what drove a man to kill three people and wound another before being fatally shot in a confrontation with officers.
The Attorney General's Office is investigating the officer-involved shooting of Carroll Tuttle.
Lori Hayden is the daughter of Skowhegan Selectwoman Darla Pickett.
The call was reported as a homicide in the Somerset County dispatch logs and was reported at 7:37 a.m. Wednesday. Both declined to speak to The Associated Press. He was undergoing surgery at a hospital in Bangor, McCausland said.
Skowhegan police closed Russell Road to traffic at the town line with Madison, and that blockade is likely to remain closed for the remainder of the day, police said.
Wednesday's shooting is the deadliest in ME since November 2015, when a gunman killed three people before taking his own life in Oakland. The 3-year-old girl was the only survivor of that rampage.