Twice as many people have been fatally shot by Maine police so far this year as in all of 2016 and 2015 combined.

Between Jan. 1 and June 7, 2017, eight people were killed by officers from seven different agencies between Arundel and Presque Isle, according to data provided by the Maine Attorney general’s office.

In 2016, Maine police killed just two people, the same number as in 2015. Likewise, the death toll in 2009 and 2012 was two.

Over the past decade, the deadliest years before this year were 2011 and 2014, when six people were fatally shot by law enforcement officers each year. Five people were killed by police in both 2008 and in 2013. Three people were killed by police in 2010.

The eighth fatality of 2017 was Mark Ellis, 54, of Orrington. He was shot and killed by Maine State Police just after 2 a.m. Wednesday, more than 12 hours after Penobscot County deputies responded to Ellis’ home at 488 Johnson Mill Road.

The three Maine State Police officers involved in the Ellis shooting, Sgt. Josh Haines, Sgt. Peter Michaud and Trooper Dave Coflesky, have been placed on administrative leave, which is routine whenever an officer is involved in the use of deadly force. All three are members of the State Police Tactical Team.

The attorney general’s office will investigate whether their use of deadly force was justified. There is no timetable under which the report must be issued. The last report was issued on Dec. 19 concerning a shooting on May 17, 2016, by a Presque Isle police officer.

Recent investigations have taken anywhere from three to 18 months to complete.

In investigating the use of deadly force by Maine law enforcement officers, the attorney general’s office has ruled in every case since 1990 that the killing was justified.

In addition to Ellis, the following people were killed this year by police, according to data provided by the attorney general’s office:

Jon M. Alspaugh, 57, of Waldoboro was killed Jan. 22, at his home on River Bend Road after allegedly exchanging gunfire with Waldoboro police officers. Police responded to a report of a domestic violence disturbance.

Kadhar Bailey, 25, of Gardiner and Ambroshia Fagre, 18, of Oakland were killed Feb. 10 by members of the Maine State Police and a Vassalboro officer after Bailey allegedly rammed a pickup truck into a state police cruiser. When they were shot, Fagre was a passenger and Bailey was driving the truck on Arnold Road. Police reportedly were called to the scene to investigate a burglary.

Chance David Baker, 22, of Portland, was shot Feb. 18 by a Portland police office on the sidewalk outside a Subway sandwich shop on St. John Street. Baker allegedly was brandishing a rifle-style pellet gun.

Brentant Lahey, 25, of Presque Isle was killed March 17, by Presque Isle police. Lahey allegedly threatened officers with a knife when they responded to the report of a disturbance at a mobile home on Skyway Street.

Roger Bubar, 65, of Belgrade was killed May 20, at his Oakland Road home after allegedly exchanging gunfire with Kennebec County sheriff’s deputies. His son, Scott Bubar, 40, of Belgrade was injured but survived.

Chad Dionne, 37, of Arundel was killed on May 29 by deputies with the York County sheriff’s office following an alleged armed confrontation. Deputies responded to a report of a disturbance at 267 Old Alfred Road.

The eight people are among the 417 people killed by police across the nation this year, according to the Washington Post’s database that is part of a project called “Fatal Force.” The newspaper’s numbers for shooting deaths by police were 991 in 2015 and 963 in 2016, which could indicate a downward trend nationally.

Philip Stinson, associate professor in the Criminal Justice Program at Bowling Green State University in Ohio, said Wednesday it was impossible to tell yet whether the deaths of eight people this year in Maine is statistically significant or not.

“It doesn’t seem that alarming at eight because you may not have another one for the rest of the year,” he said in a telephone interview. “If it were 30, that would indicate something might be going awry. Right now, it just seems odd.”

Stinson, who has been working with the Washington Post on its Fatal Force project, began his career as a police officer in Dover, New Hampshire.

“I think police officers in northern New England are used to encountering people with firearms [compared to police officers in more urban areas.]” he said. “We’re expecting a lot of our police officers today. They are asked to deal with people dealing with mental health issues, opiate and other addictions and post-traumatic stress disorder.”