LEWISTON — A judge ordered cash bail of $200,000 for an alleged “serial sex offender” Friday, an amount the judge believes is the highest amount she has ever set for bail.

Ralph Leach Androscoggin County Jail

Ralph Leach, 66, was indicted by an Androscoggin County grand jury earlier this week on a charge of gross sexual assault, a crime punishable by up to 30 years in prison.

He also is facing a charge of unlawful sexual contact, which carries a maximum sentence of 10 years, as well as a charge of visual sexual aggression, punishable by up to five years behind bars.

A misdemeanor charge alleges the unlawful sexual touching of a child younger than 14.

Leach pleaded not guilty to the charges Friday.

“These allegations are incredibly disturbing,” 8th District Court Judge Jennifer Archer told Leach, who appeared in court from Androscoggin County Jail in Auburn via videoconference.

“And the most disturbing part of it is that the victim is a child who was unable to protect herself,” Archer said.

“Children are truly the most vulnerable people out there. They cannot protect themselves and the rest of society has to step in and protect them,” she said.

Archer said she believed Leach poses, “an incredibly high risk of reoffending. I think you pose a very high risk to society at large. And the risks that you pose to children is not quantifiable.”

“I don’t know that I’ve set cast bail this high before,” Archer said.

She agreed with Assistant District Attorney Katherine Hudson-MacRae, who urged the judge to set bail at $200,000, the highest amount she has requested of the court for a criminal defendant, she said.

If Leach were able to post bail, Archer said conditions of his release would require he have no contact with the victim named in the indictment and no contact with anyone younger than 18.

Deputy District Attorney Andrew Matulis told a judge at a March hearing, after Leach’s arrest on warrants, that the man had reportedly confessed to police to having sexually assaulted several children last year and earlier this year.

In at least one case, the conduct continued for at least a year, Matulis said Leach had told police. Hudson-MacRae said Friday the three felonies stem from conduct in 2010 involving a young child.

“We have a number of victims that have been brought to the state’s attention,” Hudson-MacRae said. “It seems that Mr. Leach is a serial sex offender. We do not know and I don’t know if we will ever know the total number of victims at issue that Mr. Leach has sexually abused, the number of children he sexually abused.”

Leach did not argue Friday against the bail set by the judge.