A Kalispell man sentenced in Lincoln County to 15 years in prison for sexually abusing a young girl throughout most of her teenage years also has pleaded guilty to federal sex crimes.

Lawrence John Sheehan, 62, pleaded guilty Wednesday to transporting a minor across state lines with the intent to engage in criminal sexual activity.

He made the plea during a hearing in U.S. District Court in Missoula.

The sexual abuse - which occurred in Lincoln County, Flathead County, Idaho and Arizona - was ongoing and continuous.

It is believed to have begun in New Mexico in 2000, when the girl was just 13, and continued for seven years. In 2003, the girl gave birth to Sheehan's child, according to court documents.

Federal prosecutors say the purpose of Sheehan's transient lifestyle was so that he could abuse the girl without being caught. The girl, who often lived in tents and campgrounds, never was allowed to attend school or be home-schooled.

The girl's mother knew about the abuse, which often occurred while the three were in bed together, according to court papers.

Sheehan, who is scheduled to be sentenced in October on the federal charges, faces a mandatory minimum five years in prison and could be ordered to serve up to 30 years in addition to his state prison terms.

Sheehan previously was sentenced in October 2008 in Lincoln County District Court to 25 years in Montana State Prison with 10 years suspended. He must complete a sex offender treatment program at the prison before becoming eligible for parole.

After that sentencing, Sheehan was returned to Flathead County, where he faced additional felony charges for writing bad checks.

Sexual abuse charges filed in Flathead County, which name the same victim as in Lincoln County, were dismissed.

In November, Sheehan was sentenced in Flathead County District Court to five years in state prison to run consecutively with his state sentence for the sexual abuse.

Sheehan will begin his federal sentence after serving both his Flathead and Lincoln county sentences.

Sheehan, who wrote bad checks totaling more than $4,600 over a three-day period in July 2005, also was ordered to pay $2,000 in restitution. The checks were written to businesses across the Flathead Valley, including grocery stores, sporting goods stores, and an auto parts store.

Sheehan's defense attorney, who said Sheehan suffers mental and emotional problems, told the court his client wrote the checks because he thought the world was going to end. Sheehan has an extensive criminal record that begins in 1964 and includes assault, burglary and DUI.

Reporter Nicholas Ledden can be reached at 758-4441 or by e-mail at [email protected]