a little something about the thieves crucified alongside Jesus (I hope it's accurate)

I've been thinking about the two thieves on the cross next to Jesus. Not much is mentioned on them other than one asking for mercy and the other challenging Jesus to save himself and the thief so I did some research. Apparently according to Wikipedia in Coptic orthodoxy the good thief was called Demas and the town of San Dimas, Ca. is named after him along with several parish churches but for those with more knowledge can you tell me more?