A two-acre grass fire in Rincon Valley that spooked many residents and schoolchildren was extinguished, and an arson suspect who partially disrobed at the scene was detained, deputies and dispatchers said Wednesday .

The fire was reported at 2:13 p.m. Wednesday as "behind the cross" on a hill near Calistoga Road, said Jennifer Neal, Cal Fire dispatcher.

But the crews didn't have an exact address, so they staged firefighting equipment on Calistoga Road near Montecito Boulevard, not far from Maria Carrillo High School.

"It kind of scared the school ... they were worried," Neal said. "They didn't realize it was way up on the hill."

When fire crews found a suspect at the scene who was beginning to remove clothing, and the suspect refused to communicate, they summoned help from the Sheriff's Office helicopter Henry 1.

"He took off his shirt, that was the start of it," said Sheriff's Lt. Tim Duke. "He kept his pants on, but I don't think he was wearing shoes."

The suspect, Jordan Waugh, 23, of Oakland was restrained in a stretcher and removed from the scene by a long line dangling from a helicopter, which was deemed to be the safest option because of the rugged terrain, Duke said.

"It was unusual circumstances, but everything worked out fine," Duke said. "No one was hurt, but the potential was there."

Waugh didn't have any prior convictions, and deputies believe he acted alone, Duke said.

Waugh was booked in the Sonoma County Jail on suspicion of arson with the potential to cause bodily harm, and bail was set at $125,000.