 In March 2011 , TVline 's Michael Ausiello exclusively confirmed that previous guest actor Kevin Corrigan would be returning for the twentieth and twenty @-@ first episodes of the season . Corrigan last appeared in the season 's twelfth episode " Concentrate and Ask Again " ; his role in " 6 : 02 AM EST " and the following week 's episode " The Last Sam Weiss " marked his sixth and seventh appearances on Fringe , respectively . 
