A repeat sex offender from Kentucky was sentenced to 20 years in federal prison Wednesday in a case that was investigated by an undercover Roswell police officer, officials said.

Mark Allen Johnson, 31, of Bowling Green, was convicted on several counts, including distribution of child pornography, attempted enticement and attempted transfer of obscene material to a minor, acting U.S. Attorney for the Western District of Kentucky Michael A. Bennett said.

In his announcement, Bennet explicitly thanked the Roswell Police Department for its work in the investigation leading to Johnson’s conviction.

The federal case began after Johnson had already pleaded guilty in Kentucky state court to one count of prohibited use of an electronic communication system to procure a minor. Johnson entered that plea in January 2020, but the next month, he sent a video of child pornography to an undercover Roswell officer who he believed was a 13-year-old girl, according to Bennett.

While he continued chatting online with the Roswell officer, Johnson was also chatting with an undercover FBI agent who he also believed was a minor. The conversations with the FBI agent dated to December 2019 and included offers to meet and engage in sex acts.

“The investigations combined when, after the FBI conducted a federal search warrant at Johnson’s Bowling Green residence, Johnson provided the Georgia undercover with a copy of the federal search warrant,” Bennett’s announcement said.

Johnson told the Roswell officer that he had a new phone number because the FBI had confiscated his old phone during a search. He was arrested shortly after that exchange, according to the announcement.

“The prosecution team’s effort resulted in a lengthy 20-year period of incarceration followed by federal supervision for life. The community is safer now for all citizens, especially our children,” Bennett said.

After his sentencing in federal court, Johnson is scheduled to be sentenced for the state charge to which he pled guilty in January 2020. The state sentence could be as long as five years, to be served after the 20-year federal sentence, the announcement said.