Coleman, a federal appointee, made the announcement Monday, days before the Trump administration prepares to leave to make way for the incoming Biden administration.
They're facing federal charges of armed drug trafficking.
Robert Alan Thompson, 33, of Hodgenville, told investigators that he had received two pictures of boys aged 13 to 14, from Matthew Lyons, 33, who in April was charged with offenses including sex trafficking of a child, authorities said.
Tevin R. Patton, of Memphis, is facing federal charges of being a convicted felon in possession of a firearm.
David M. Schwartz, 48, a former officer with Louisville Metro Department of Corrections, has been sentenced to two years, while his former supervisor, Donna K. Gentry, 55, was sentenced to eight months of home confinement.
Seven-year-old Dequante Hobbs was eating cake at the kitchen table when a bullet came through the window of his West Madison Street home.
Elijah Eubanks, 21, previously had been convicted for attempted murder in the incident and is serving a 15-year sentence.
U.S. Attorney Russell Coleman told the public to "stay tuned" because there's "much more to come."