LEWISTON – Maine’s four Democratic candidates for governor shied away from direct attacks Thursday night in their final debate of the primary campaign.

Rosa Scarcelli of Portland, who has never held elective office, said she is the only Democrat who can bring real change to state government.

The candidates — Scarcelli, Senate President Elizabeth Mitchell, former Attorney General Steve Rowe and former state Conservation Commissioner Patrick McGowan — asked each other mostly easy questions.

One of the few back-and-forth exchanges came when Mitchell asked Scarcelli whether her proposal to increase class sizes would give private-school students an unfair educational advantage over public schoolchildren.

“Performance is based on the quality of the teacher,” Scarcelli said, not on class size.

Mitchell asked McGowan if he is proud of his state government service. McGowan has run ads criticizing “career politicians.”

“There is a huge frustration amongst people,” he said. “People want to see a new approach from the top down in the Legislature.”

Moderator Jennifer Rooks asked Rowe whether he would allow a commission to investigate police-involved shootings. Rooks said that while Rowe was attorney general, his office always found in favor of police.

“Every decision we made was based on the facts in the case,” he said.