Russel Winters ran a large corporation, and had associations with Wolfram and Heart. He liked to get young women to trust him, and then kill them. Angel started watching out for a young woman named Tina who said Winters was constantly harassing her. Tina trusted Angel originally, but then began to mistrust him, eventually finding out he was a vampire. Scared, she went to Winters, who she didn't know was a vampire. He, however, vamped out and killed her. Later that evening, he invited Cordelia up to his mansion, with the intention of feeding off her. Angel found out, and was able to rescue her in time. The next day, Angel walked into Winter's office building, pushed him out a window, and walked away. The sunlight killed Winters before he even hit the ground.
I believe Winters was quite old, possibly 1000 years. That however is just a guess. His face and colouring just seemed a little more demonic, and to run a huge corporation like that, I'd think he might have been around for a while.