MURFREESBORO, Tenn. (AP) -- A Rutherford County judge sentenced a convicted sex offender already in prison for attempted child rape to an additional 20 years for his conviction of child molestation.

The Daily News Journal reports 34-year-old Marcus Darnell Smartt was sentenced on Friday after being convicted in December of molesting two 6-year-old children at his home in Murfreesboro.

He was already serving a 10-year sentence on an unrelated count of attempted child rape when his former girlfriend told police about incidents that occurred in the early 2000s when she and her children shared a home with Smartt.

The mother of the children submitted a letter to the judge asking for the maximum sentence on each of the counts, including two counts of aggravated sexual battery and two counts of soliciting a minor.