PROVO — Three adults were arrested after police say they allowed a 12-year-old they were baby-sitting to smoke marijuana.

American Fork police received a call Monday night and responded to a mobile home in a campground area in southeast American Fork, said American Fork Police Sgt. Gregg Ludlow. Officers reported a heavy odor of marijuana in the air.

When police asked the adults — ages 18, 19 and 22 — about the 12-year-old boy with them, they initially said he had come over after they had smoked.

That's the same story the boy gave, Ludlow said.

"(The boy) continued to deny it," Ludlow said. "He was probably afraid he would get them in trouble."

However, during the course of the officers' investigation, police discovered the boy had been there the entire time and had even smoked marijuana with them, Ludlow said.

Two of the adults were supposed to be watching the boy while his mom was out of town, and the other adult was a relative, Ludlow said. After the arrests, the boy was released to his grandmother.

"Know who your kids are with," Ludlow reminded parents. "Be involved in their lives, know who they're hanging out with. Be nosy."

The three individuals were booked into the Utah County Jail for investigation of child endangerment and possession of marijuana and drug paraphernalia. The child was not cited, Ludlow said.