Peter Harper was a victim of Dark!Charlie.
Peter is (or was) a District Attorney residing in Topeka, Kansas. Years ago, he worked on a case involving a drunk driver who crashed into another vehicle, killing the driver and rendering the passenger brain-dead. The victims were the Middletons, who were on their way to pick up their 12 years old daughter.
For reasons Peter could not understand, the case never went to trial and all the evidence and files were sealed. Peter was paid lots of money to keep quiet about it.
In 2015, while Peter was at home getting ready for bed, a red-haired woman attacked him and began torturing him, asking him about the case. He insisted he knew nothing about it. Desperate, he gave up a name anyway - Councilwoman Barbara Cordy - and was released.
By morning, Peter discovered there was no record of the case. He was soon approached by Sam and Dean Winchester, disguised as FBI agents. He told them as much as he could, but refused to reveal what name he gave to his attacker in fear of being disbarred. When Dean threatened him with violence, Peter finally confessed.