Incorrect. Matt never trained with DeathClutch. Pat was invited to DeathClutch and did train there.
Mitrione left Roufusport because of a lack of heavyweights. He trained there with Pat, but Pat was invited to join DeathClutch - where he stayed until they closed. Mitrione lives in Indianapolis and at the time there were not many gyms or heavies for him to battle. He would get in workouts where he could - like renting out a room for the day at a YMCA and wrestling Sean McCorkle. Mitrione spent a month or two in Las Vegas at Xtreme Couture working with that crew and specifically with coach Neil Melanson. After that, Mitrione was invited to join Blackzilians and trains there for his specific fight camps. During the rest of the year, Mitrione recently opened his own gym called Integrated Fighting Academy in Indianapolis, Indiana.
As for when he left Roufusport? It was at the very least before his Morecraft bout in Pittsburgh. He was training with Xtreme Couture then.
As for Pat Barry, he joined DeathClutch. DeathClutch closed. Pat stayed in Minnesota and trained with Erik Paulson at the Academy. Pat began splitting time training with Trevor Wittman's crew in Colorado at Grudge and, most recently, Pat trained some at Jackson-Winkeljons in AB, NM.