A convicted sex offender on Pennsylvania’s Megan’s Law list has been accused of molesting four girls, ages 5-10, over a two-year-period.

John Garman Shirk, 61, of 25 Pine Ridge Lane, Center Township, told police he took two 5-year-old girls on a tractor ride in a field at 6 p.m. Sept. 27, during which he pulled up their dresses and fondled the girls as they took turns sitting on his lap.

Shirk allegedly told state police at Selinsgrove that he had fondled the girls in the same way on at least two previous occasions in the previous three weeks.

Shirk also told police he had similar contact with two girls who reside in Indiana, according to court documents. The victims, now ages 10 and 9, visited Shirk every summer for the past three years. The most recent visit occurred in July, when he took the girls for a ride on the tractor and put his hands on their clothing above their genitals while they sat on his lap.

Shirk said he did the same thing the two previous years they visited, in 2007 and 2008.

All incidents occurred between July 2007 and Sept. 27 of this year, at his home.

He is being held at Snyder County Jail on $750,000 bail. Shirk faces 10 counts each of indecent assault and corruption of minors, and another 10 counts of indecent assault.

Shirk is included on the Pennsylvania Megan’s Law Web site for a 1999 conviction for indecent assault case in Union County.