HARRISBURG — A retired Gettysburg College professor will spend two to four years in prison for trying to meet a 15-year-old boy for sex in what was really an online sting run by the state attorney general’s office.

Robert Viti, 69, was sentenced Thursday by a Dauphin County judge.

The Harrisburg man retired from the college, where he taught French and other courses, in 2011. But he had returned to teach some classes part-time in 2014 before his arrest was announced in August. Viti was sentenced after previously pleading guilty to unlawful contact with a minor and two other offenses.