NAMPA -- A Nampa man convicted of preying on preteen girls was sentenced Tuesday to 40 years in prison.

Quentin Nava, 39, will spend at least 18 years of that sentence behind bars before he can become eligible for parole.

Nava was arrested in November 2016 after police learned he had inappropriately touched two children at a house where he was staying as a guest. Prosecutors say the defendant touched the girls' buttocks and privates while they were sleeping.

Nava was already a registered sex offender, having been convicted of rape of a girl under the age of 16 in 2000. He was convicted of the new charges - lewd conduct with a child and sexual abuse of a minor - after a jury trial in May.

"The defendant in this case is a registered sex offender who didn't think twice about preying on young girls again," Prosecutor Bryan Taylor said. "It highlights importance of having sex offender registries like the one in Canyon County that allow people to check on individuals by name or location. These types of tools are out there for the protection of society, and I encourage everyone to use them and use them often."

Judge George Southworth said Tuesday that a long prison sentence was appropriate.

"Because of the nature of this case, I'm ordering that 18 years be fixed so the defendant will be in his late 50s before he is entitled to parole," he said.

In addition to the prison time, Nava was ordered to pay court costs and a $10,000 civil penalty, and have no contact with his young victims or other female children.