Man pleads guilty to sexually assaulting 4-year-old Marengo girl when 17, sentenced to 15 years in prison

A 25-year-old Rockton man pleaded guilty Wednesday to sexually assaulting a 4-year-old Marengo girl in 2014 when he was 17 years old and was sentenced to 15 years in prison.

Nathan N. Rieken, of Rockton, entered a negotiated plea to predatory sexual assault of a child, a Class X felony.

At the end of his sentence, he could be declared a sexually violent person and be held for an undetermined time. Either way, he will also have to register as a sexual offender for life.

In exchange for his guilty plea, additional counts of predatory sexual assault of a child, the Class X felony; three counts of criminal sexual assault, a Class 1 felony; and three counts of aggravated criminal sexual abuse, a Class 2 felony were dismissed.

Required to serve 85% of the sentence under the state’s truth-in-sentencing guidelines, Rieken will be released in 12 3/4 years, Assistant State’s Attorney Ashley Romito said.

The parents of the child were present in the McHenry County courtroom during the sentencing Wednesday.

He “stole the innocence” of our children, the father said, adding he will always question how this abuse will affect his children in the future.

The children’s mother said she is “heartbroken and feel[s] betrayed in the worst way ever.”