NEW YORK (AP) – A convicted sex offender described by prosecutors as a serial New York City subway “grinder” and “groper” has been sentenced to two years to life in prison.

Freddie Johnson was sentenced Wednesday in Manhattan’s state Supreme Court after pleading guilty last month to persistent sexual abuse. Police arrested the 50-year-old ex-con on a train at 59th Street and Lexington Avenue in April 2008 as he shoved his pelvis into a young woman’s buttocks.

Police said Johnson had been arrested 53 other times, mostly on charges of groping women.

Because of his conviction record and guilty plea to persistent sexual abuse, the judge was allowed to impose a sentence that will keep Johnson on parole for life if he is released.

Defense lawyer Edward Land says Johnson hopes to get psychiatric help in prison.

AP-ES-02-18-09 1801EST