Paul Barrett made his first appearance in The Flash #130 - Who Doomed the Flash? He was created by Carmine Infantino and John Broome
Paul Barrett is an attorney in the Central City who had been representing Mirror Master (Scudder) in court. During the trail of Mirror Master, Barrett was hypnotized by Scudder, who used a series of small mirrors to put Barrett under his control.
Barrett began listening to Scudder's orders and aided him in several schemes. Utilizing a variety of costumes such as Trickster's, Top's and Captain Boomerang's he made Flash believe that the heroes he had jailed had somehow broken out.
Eventually Barrett encountered Flash and used some sort of smoke/gas to knock Flash out. He then stole Flashes costume and delivered it to Mirror Master who switched places with Barrett, thus letting Scudder out of jail while Barrett was left in the cell.
Once he had recovered from Mirror Master's control he was able to help the true Flash by telling him where Scudder's next target was, a memory still in the back of his mind due to Scudder's mental manipulations.