A Willits man was arrested on suspicion of molesting a 4-year-old boy, the Mendocino County Sheriff's Department said Tuesday.

Kyle Andrew Gillaspie, 26, was arrested on suspicion of lewd conduct with a child and booked into Mendocino County Jail in lieu of $100,000 bail.

The arrest stemmed from an incident Sunday in which the boy was dropped off for baby-sitting by one of his parents at a friend's home on Cobb Drive in Willits.

Four hours later, the parent arrived to retrieve the boy and learned he had been left alone with Gillaspie.

At some point during the four hours, the friend found the child alone with Gillaspie and became suspicious because the child was partially unclothed, according to the Sheriff's Department.

After authorities were contacted, investigators interviewed the child and found probable cause to believe Gillaspie sexually abused the child.