PINE RIDGE, S.D. (KELO) — An Iowa man will spend nearly 3 decades behind bars after pleading guilty to sex crimes.

The U.S. Attorney’s Office says that in 2010, 66-year-old Douglas Hennigar moved to the Pine Ridge Reservation after meeting the victims’ relative.

He then sexually abused 2 girls between the ages of 5 and 10.

Authorities say the abuse happened for years both on and off the reservation.

Hennigar was sentenced to 27 years in federal prison followed by 10 years of supervised release.