BOSTON — A former leader of the Boy Scouts has been sentenced to 33 years in federal prison for sexually exploiting more than a dozen children through a social media app, federal prosecutors said Tuesday.

In addition to his prison term, Matthew Murphy, 25, of Whitman, was also sentenced Monday in U.S. District Court in Boston to 10 years of probation, according to a statement from the U.S. attorney's office.

The investigation began in 2017 when law enforcement learned that Murphy had posed as a teenage girl on Snapchat to extort nude photographs from a middle school boy in Massachusetts, prosecutors said.

Through the investigation, authorities found that that Murphy used five separate Snapchat accounts to sexually exploit at least 15 children.

He knew some of the children and their families through his connection to local Boy Scouts troops, prosecutors said.

He pleaded guilty in January 2020 to multiple counts of sexual exploitation of children.