A convicted sex offender will face two felony charges in Flathead County District Court after a police investigation revealed he allegedly molested a 5-year-old Kalispell boy.

Jason Dean Franks, 41, was arrested in Missoula on Tuesday for failing to register as a sex offender. He is being held in Missoula County Jail.

Also on Tuesday, prosecutors with the Flathead County Attorney’s Office charged him with felony sexual assault and sexual intercourse without consent following a Kalispell Police Department investigation that alleged he began having sexual contact with a boy in 2009 when the youth was 4 years old.

County Attorney’s Office Administrator Vickie Eggum said a warrant will be issued to extradite Franks to Flathead County, though it is not yet clear whether or not he will first face the charge of failing to register in Missoula County.

According to court documents, Franks moved in with a Kalispell woman and her two boys in August 2009. The mother later told investigating officers that she was aware he was a sex offender. Franks had been convicted of having sex with an underage girl in 1993, according to court documents.

On April 13, the mother reported an incident on March 15 in which her 7-year-old son accused Franks of having sexual contact with his younger brother while she was at work.

At the same time, she reported an incident that allegedly occurred in January after she heard her boys yell while in a public restroom with Franks.

After demanding he open the locked door, she discovered that Franks was naked and that her youngest son — 4 at the time — was having sexual contact with him, according to court documents.

“At the time, she did not think it was what it looked like so [she] did not take any action,” according to an investigation by a Kalispell detective.

On Oct. 28, a Kalispell detective interviewed the older brother, who said Franks frequently molested the 5-year-old when their mother was away. Subsequent investigation revealed that the 5-year-old had told a counselor about the alleged abuse.

The maximum penalty for sexual assault is 100 years in prison and a $50,000 fine. Felony sexual intercourse without consent also carries a maximum penalty of 100 years in prison.