(CNN) -- The founder of a national charity to help homeless children has been accused of sexually abusing a minor he was supervising, police in Aurora, Colorado, said.
And investigators said they're concerned Richard Lee Koca Sr. may have abused other children during his decades of work with nonprofits serving children, from the Boy Scouts to his own StandUp for Kids.
Koca, 69, is accused of one count of sexual assault on a child by one in a position of trust, according to a police statement Monday. He was arrested Saturday in an investigation that began in late August, police said.
Police did not say whether the child was part of Koca's StandUp for Kids charity or elaborate on the circumstances of the alleged abuse.
Koca was being held Tuesday in lieu of $250,000 bond at the Arapahoe County jail, according to jail records. He is scheduled to appear in Arapahoe County District Court on Friday.
According to police, Koca is a retired U.S. Navy officer who has lived in Panama, Venezuela, Spain, Italy, England, San Diego, Houston, Atlanta and Aurora.
While in Panama, police say, Koca was a scout master for a Boy Scouts program and volunteered for an unidentified orphanage in England. He was also involved in an Explorer scout program in San Diego, police said.
Police were asking for help from the public and media in identifying other possible victims.
The StandUp for Kids website is not active, but according to copies of the website maintained by Google and the Internet Archive website, Koca founded the organization in 1990 when he arrived in San Diego.
He was on its board of directors until Monday when the group learned of the charges, interim director Justine Madison said in a statement Tuesday.
Madison said the group was aware of the arrest but had no information about the accusations. The group has not been contacted by police, Madison said in the statement.
Koca retired as the group's CEO in 2010, according to the statement.
In a "Founder's Message" on archived copies of the website maintained by Google and the Internet Archive, Koca apparently wrote about the risks of sexual exploitation of homeless children,.
"We know first hand that once on the streets, young people are at even higher risk of being physically and/or sexually victimized, of self-medicating with drugs or alcohol to reduce emotional pain," Koca apparently wrote. "Some even attempt suicide and often engage in act of 'survival' sex to meet their need for food, shelter, and clothing."
According to the group's 2010 tax filings, StandUp for Kids provided food, clothing, showers, transportation and other services to more than 15,000 children through a network of drop-in centers, alternative schools and street outreach programs.
It claimed total revenue of $1.7 million in 2010, the last year for which tax records are available online.