WASHINGTON — The former teacher’s aide and coach already convicted on state charges he sexually assaulted children in Charles County schools entered a guilty plea in federal court on Tuesday.

Federal prosecutors said they’ve struck a deal with Carlos Bell, 30, and are asking that he be sentenced to 150 years for creating child pornography involving 10 children.

Bell’s guilty plea in front of U.S. District Judge Paul W. Grimm was not a surprise. When he arranged a plea deal at the state level with Bell earlier this month, Tony Covington, the state’s attorney for Charles County, said a guilty plea was coming at the federal level, in part to save the victims in the case from having to testify.

Bell admitted to coercing the 10 children to take part in illicit acts for the purpose of creating child pornography over a two-year period, federal prosecutors said.

During those two years — January 2014 though December 2016 — court documents show that Bell was employed as a teacher’s aide and track coach in Charles County schools.

Bell is already facing a possible sentence of 190 years in the state case against him. He’ll be sentenced in the federal case in late March.