A Massachusetts State Police trooper was arrested in Plympton last week on domestic violence charges tied to the assault of a child, according to a criminal complaint.

Plympton police say Trooper Michael Gagnon, 36, was arrested at a home in their town on Nov. 25. The complaint alleges that Gagnon hit a child in his care in the face, then told the child not to tell his mother, or lie and say it was caused by a whiffle ball bat.

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The incident happened sometime between mid-August and September, according to the complaint, but wasn't reported until the victim disclosed the alleged abuse to a therapist.

Gagnon was charged with assault and battery and assault and battery of a child under 14. He was relieved of his duty

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