BELFAST —  A Winterport man will spend the next 22 years behind bars for the sexual assault, exploitation of multiple children after pleading guilty to several crimes as part of a plea deal in Waldo County Unified Court Oct. 2. 

Steven R. Mathis, 36, was sentenced to 22 years in prison for two count of gross sexual assault and two counts of sexual exploitation of a minor under 12. He will serve five years for possession of sexually explicit materials. 

The sentences will run concurrently. Mathis is also facing a federal case related to his crimes.

An investigation by the Maine State Police Computer Crime Unit began Sept. 13, 2019, when a CyberTip was received from the National Center for Missing and Exploited Children, according to an affidavit filed by the investigating officer. A username associated with Mathis had reportedly uploaded and disseminated an image of a child being sexually exploited to a social media site, which made the initial report to NCMEC. 

The incident was deemed a low priority on the investigating officers' workload, and thus the investigation did not begin until Nov. 11, 2021, according to the affidavit. It was revealed during the investigation that a number of people in Mathis’ life had voiced concerns over rumors about Mathis, according to the report. 

One complainant reportedly told officers that Mathis had been talking about a minor relative in a sexual manner, although Mathis denied that later in an interview. Mathis did admit that he was a part of a fantasy chat with someone online, the affadavit.

Over the course of the interview, Mathis reportedly admitted to having viewed sexually explicit material of minors online.

When asked whether he had sexually abused children, Mathis reportedly minimized and denied the abuse, before ultimately admitting to sexually abusing three minor children, who were known to him. The last occurrence reportedly took place just two weeks before police arrived at his home. 

One of the children he abused is non-verbal, another was under three years of age at the time of the sexual abuse. Mathis also admitted exposing himself to at least two of the children. Mathis admitted to uploading images from the sexual assaults. 

Computers and multiple cell phones were seized from the home and taken as evidence. 

A member of Mathis’ family reportedly told police that Mathis had fled to live with his father in Texas, taking a bus from Bangor to Boston, then to Texas. 

Mathis will serve his time at the Maine State Prison, and will be a lifelong member of the Sexual Offender Registry. 

Erica Thoms can be reached at news@penbaypilot.com