OKLAHOMA CITY — An Oklahoma man accused of sexually abusing several children at a Kenyan orphanage where he volunteered confessed to his misdeeds in writing, a federal prosecutor told jurors Wednesday at the outset of the trial.

Assistant U.S. Attorney Don Gifford spent part of his opening arguments reading excerpts of 20-year-old Matthew Lane Durham’s confession, which Durham’s lawyer says isn’t true and was coerced.

“I would take her to the bathroom at night and hold her down and rape her,” Gifford said, reading a section pertaining to the alleged assault of a 12-year-old girl.

Quoting another that pertained to a boy at the Upendo Children’s Home in the Kenyan capital of Nairobi, Gifford read: “At night I took him to the bathroom and had him perform oral sex on me.”

Durham, of Edmond, has pleaded not guilty to the 17 charges he faces, including aggravated sexual abuse and engaging in illicit sexual conduct in foreign places. If convicted on all charges, he faces up to life in prison.

Six of the children, who speak Swahili, were scheduled to testify through an interpreter. The first began to testify after opening statements concluded, but not before the judge cleared the gallery and closed the courtroom to the public and media.

During his opening statement, defense lawyer Stephen Jones said Durham is innocent and that he only confessed to the crimes because he was under duress. He said officials at the orphanage had detained and isolated him, and had taken away his passport.

“He’s in fear for his life,” Jones said. He described Durham as “an emotionally vulnerable teenager” who was struggling with “sexual identity and development” while also being a devout Christian.

Jones said the orphanage, on hearing the allegations, initially didn’t notify police, medical officials or the U.S. Embassy, and that others who lived in the Upendo home didn’t witness any wrongdoing alleged to have occurred.

“They never saw anything in the close confines,” Jones said.

U.S. District Judge David Russell said the trial could last up to two weeks. In addition to the six children, orphanage officials and 10 missionaries are among the 39 witnesses prosecutors intend to call to the stand.

Jones has said Durham will testify.

The judge agreed last week to close the courtroom during the children’s testimony after prosecutors complained Durham and his family had discussed a plan to “pack the courtroom” with supporters. The government feared that testifying in open court could pose “substantial psychological harm” to the children.

Durham had volunteered at the orphanage since 2012. Prosecutors allege he assaulted children last year.