SAN FRANCISCO » One of two men accused of sexually abusing a 15-year-old girl, keeping her captive in a metal box and forcing her to work on a large Northern California marijuana growing operation has confessed, federal prosecutors said in court documents.

Prosecutors say Ryan Balletto, 30, and Patrick Pearmain, 24, both had sex with the girl who was cutting marijuana buds for them at Balletto’s Lake County property.

The two were scheduled to enter pleas today in federal court in San Francisco. They are charged with marijuana possession and using a minor in drug operations.

But prosecutors said Balletto already has confessed, according to court documents arguing Balletto and Pearmain should remain behind bars during the case.

"The government … has a recorded, Mirandized confession by Balletto, a recorded statement from the minor victim, and multiple recorded statements from others who were working on the grow site," prosecutors wrote.

Authorities in Lake County learned about the case when the Los Angeles Police Department advised that Balletto might have kidnapped her.

Deputies visited Balletto’s home asking about the missing girl April 29, the complaint said, and she called authorities the next day to say she was OK and in Sacramento.

LAPD investigators traced the call and police located the girl at a West Sacramento hotel, where authorities arrested Pearmain, the complaint said.

Back at Balletto’s pot farm, officers found "equipment consistent with sexual bondage and sadomasochism," including a rack "presumably used to attach a human to the device and immobilize them." Near the rack officers found a towel with blood stains.

The girl, described as a runaway from the Los Angeles area, told investigators she was locked in a 4-by-2-by-2-foot box. Holes had been drilled in the box, and water was run through the box to wash her without letting her out, the complaint said.

Investigators found human hair inside the box, where prosecutors said the girl was imprisoned "on multiple occasions, for days."

A message left this morning for Balletto’s attorney, Jodi Linker of the Office of the Federal Public Defender, was not immediately returned. Pearmain’s lawyer, Robert Waggener, also did not return a call.

Hundreds of marijuana plants and several firearms, including AR-15-style assault rifles and body armor were found as part of the investigation.

Prosecutors described Balletto as an ex-Marine who was preparing for an extended battle.

"The presence of so many weapons on the grow site, including two assault rifles and eleven loaded 20- and 30-round magazines … indicate that Balletto was prepared to engage in an extended gun battle," prosecutors wrote.