A 43-year-old Delaware County man was sentenced Tuesday in federal court in Philadelphia to 90 years in prison for making child pornography of a 7-year-old girl he had sexually assaulted, prosecutors said.

Matthew Maffei, of Aston, had previously pleaded guilty to making and possessing child pornography of the daughter of a childhood friend.

Maffei assaulted the girl while her parents slept in the next bedroom of their Middletown home and on one occasion forced her 5-year-old brother to watch, prosecutors said. He threatened to kill them if they told their parents.

U.S. District Judge Mitchell S. Goldberg called his crimes "unspeakable" and asked the children's parents to assure them that "this defendant will never in his lifetime be released from custody," prosecutors said.