A U.S. jury found a Christian missionary from Oregon guilty Wednesday of multiple sex abuse charges for molesting children living at an unlicensed Cambodian orphanage that he operated in Phnom Penh over a period of years.

Daniel Stephen Johnson, 40, was convicted of six counts of engaging in illicit sexual conduct in a foreign place and one count each of travel with the intent to engage in illicit sexual conduct and aggravated sexual assault with children. He faces a minimum of 30 years in prison when sentenced in August in Eugene, Oregon.

Federal public defender Craig Weinerman did not return calls or e-mail from The Associated Press seeking comment after business hours Wednesday. His co-counsel, Lisa Maxfield, declined comment.

U.S. authorities said nine Cambodian children ranging in age from 7 to 18 have disclosed Johnson's abuse or past abuse in lengthy interviews with trained child-forensic interviewers. The FBI launched an extensive investigation of Johnson and his potential victims after learning of the case in 2013, the U.S. Attorney's Office in Portland said.

"The despicable nature of this defendant's conduct is beyond understanding," said Billy Williams, U.S. attorney for the District of Oregon.

"The fact that this defendant abused children under the guise of being a missionary and orphanage director is appalling."

Johnson first molested a child at the orphanage during a trip in 2005, according to court documents.

Local law enforcement issued a warrant for Johnson's arrest in an unrelated matter in 2013 in Lincoln County, Oregon. Johnson was located overseas and his passport as revoked based on the Oregon warrant. It wasn't immediately clear what the local case involved and a spokesman for the U.S. Attorney's Office didn't return a request for details.

The FBI then partnered with a non-profit that combats child exploitation in Cambodia and the Cambodian National Police to locate Johnson in Phnom Penh.

He was arrested in 2013 by Cambodian authorities and indicted the following year in the U.S. on one count of engaging in illicit sexual conduct in a foreign place.

Johnson was extradited to the U.S. after completing a one-year prison sentence in Cambodia as U.S. authorities sought to build their case.

Seven more charges were added in 2017.

While in custody, Johnson tried to tamper with witnesses and contact his victims online, bribing them with gifts and promises of money to change their testimony, the U.S. Attorney's Office said in a statement.

More details on the case were not immediately available and many court documents in the case are filed under seal.