"We wanted 64 years for rape," said Colop. "But because the abuse was against boys (and not girls), it is not called rape but rather dishonest abuse, and the sentence is lower."
Colop said Kotouc was arrested in 2008 with the four boys in bed.
He said other boys also had testified against the defendant.
"He had various groups of boys he sexually abused," the prosecutor said, adding that "when they got to 13 or 14 years old, he didn't include them anymore" in the groups.
Kotouc also faces a $12,000 fine. It was unclear whether he planned to appeal the sentence.
Colop said Kotouc arrived in the small Indian community of San Miguel Chicaj in 2006, where he provided medical care to residents, apparently as a way to gain their confidence.
Kotouc was identified as a doctor with West Virginia University's medical school when he was arrested in 2008, but the school said he was on leave and not on a university-affiliated mission.