A 44-year-old youth program volunteer from Ramsey has been charged with sexually abusing four boys age 13 or younger in numerous incidents dating from within the past year to as far back as 1995.

The suspect met one of his alleged victims through his 1989-1993 association with the Big Brothers organization and another while mentoring a boy about aviation, according to documents filed in Anoka County District Court.

Chad Geyen was charged Tuesday with three counts of first-degree criminal sexual conduct. As the investigation continues, authorities said it’s highly likely they will find more possible victims.

“It’s pretty unusual [for abuse cases] to go undetected after having this much contact with victims over such a long period of time,” Anoka County Sheriff’s Cmdr. Paul Sommer said. “There were hundreds of alleged incidents.”

Geyen was arrested peacefully on Monday at his home and appeared in court Wednesday. Bail was set at $500,000 with conditions that bar him from contact with his accusers or any minors and a requirement that he turn in his passport and pilot’s license. Bail with no conditions was set at $1.5 million.

Earlier this month, investigators interviewed two boys who said they were abused by Geyen within the past 12 months and two men who said they were abused by him as boys. The two boys are brothers, ages 11 and 8, and the two men are cousins, in their mid-20s, according to the criminal complaint. One of the cousins was a ring bearer at Geyen’s wedding many years ago and became his foster child for a time, the complaint said.

County Attorney Tony Palumbo said he expects to see more cases referred to his office against Geyen, citing a pattern of behavior over a lengthy period of time.

“The allegations are certainly shocking,” Palumbo said. “If proven, it would make this a crime which certainly involves a severe punishment.”

Ryan Garry, Geyen’s attorney, said his client is “presumed 100 percent” innocent. Garry said he has yet to look at the evidence in the case or conduct his own investigation.

Geyen’s relatives attended Wednesday’s court appearance in Anoka. “His family supports him,” Garry said. “You can imagine allegations such as these are very difficult to deal with on both sides of the coin, including his family.”

Mentored kids about aviation

The Sheriff’s Office said that, along with his work in Big Brothers from 1989 to 1993, Geyen has recently been part of a group called the Young Eagles through the Blaine airport. That program serves youths interested in aviation.

According to the charges, some of the alleged assaults occurred at Geyen’s home, his cabin and at the airport. One of the men said he was assaulted hundreds of times starting when he was 8 years old and continuing until he was 13. The abuse involved many acts of oral and anal sex, the complaint said.

In a statement issued Wednesday, Big Brothers Big Sisters of the Greater Twin Cities said it has “no record that [Geyen] was involved in this organization.” However, organization spokeswoman Maggie Karl said that the absence of a record doesn’t mean he was not a Big Brother and that she was checking further.

The statement added that “our volunteers and staff undergo thorough screening interviews and background checks [and] as part of the orientation and training process, volunteers, mentees and their parents/guardians receive personal safety awareness education.”

Young Eagles flights are sponsored by the Wisconsin-based Experimental Aircraft Association, and there are chapters throughout Minnesota and around the country that match pilots — EAA members and nonmembers — with children ages 8 to 17 for free flights as a way to interest young people in aviation.

Dick McKenney, vice president of the Blaine airport’s EAA chapter, said Wednesday that volunteer pilots are checked to ensure they are fully licensed to fly but are not subject to criminal background checks. Federal Aviation Administration records show that Geyen and his wife own a four-seat Cessna aircraft.

Chapter President Randy Delfel added that he was told Geyen had no criminal record that a background check would detect. “You roll the dice with what you do in this world,” Delfel added, noting that Geyen was not a member of his chapter. “What do you do? As a chapter, you try to do the best you can.”

Notified this month

The Sheriff’s Office said it became aware of the alleged assaults in early November and has yet to determine how many children Geyen, who works in the information technology field, may have had contact with or whether there are more who have yet to come forward.

Any person who may have information about Geyen is asked to contact the Sheriff’s Office at 763-427-1212.

According to the complaint:

• One boy, now 11, said Geyen abused him “numerous times” when he was alone with the defendant at the man’s home, cabin and at the airport.

• A boy now 8 said he watched pornography with Geyen. He said that while he was swimming with Geyen, the defendant wanted to wash him. The boy said the incidents occurred within the past year.

• A 25-year-old man told law enforcement that he met Geyen through his cousin, now 26, who was 7 or 8 at the time. The younger cousin said that Geyen abused him from ages 8 to 13 and that it occurred “hundreds of times” at Geyen’s home and cabin.

• The older cousin said he met Geyen through the Big Brothers program when he was 5 and became a foster child to the defendant and a ring bearer in Geyen’s wedding. He said Geyen abused him at least 100 times and in one instance he saw Geyen assault his cousin.

Sommer said no children were found at Geyen’s home who needed to be placed in protective custody. Geyen and his wife, Terese, have two adopted children who are now adults. The Geyens became the guardian for one of them when he turned 18 in 2008 because he is developmentally disabled, according to court documents.