Is There Such a Thing as Pre-Abusive Behavior?

The story that prompted the titular question:
S*, D* and I are all members of an inter-collegiate sports team. About a year ago, S* and D* began dating. I never liked D* since we had worked together and he had been horribly condescending and rude to me, but S liked him so I tried to keep my mouth shut. I hung out with S* for part of the summer and she seemed happy. She was working closely with another friend, A* (male). By the end of the summer, S* and D* had broken up. D* told anothe friend of ours that S* had cheated on him with A*.
S* told me a different story: While she and D* started out well, she started to feel that he was being a little to controlling. He told her not to talk to her ex-boyfriend, even though S* and her ex had remained close friends. He didn’t like her two best friends either and tried to get her away from them. One time, S* came in with a henna design on her hand (her two best friends are Indian) and D* freaked out at her, saying it “wasn’t appropriate” when they were visiting D*’s parents. D* also went behind her back to A* and tried to convince A* to stop working with S*, telling him S* was lazy and not a good coworker. All the while, he was trying to make S* work with him. He frequently insulted me and all of S*’s friends, yet got really angry when S* said something about a friend of his (it wasn’t even meant to be an insult). He constantly threatened to tell people S* had cheated on him with A*. S* didn’t want to talk about it, but she did say he pressured her “in other ways” as well.

As I said, S* did break up with D* eventually. She did it over the phone because she was too scared to do it in person. D* told her she had to come get her stuff from his room, but S* was afraid to go alone. I volunteered to go with her, but eventually her parents intervened and told her that they would replace whatever she left and not to worry about it. Meanwhile, D* has persisted in telling everyone that S* cheated on him. In particular, he has been frequently bothering S*’s new training partner.
S* is now safe and happy and pretty much wants to forget the whole thing. She tried to patch it up with D* but he is very pointedly ignoring her. Meanwhile, everyone knows D* has set his sights on another, younger woman (K*)(he was going after her even when S* and D* were dating, and making K* feel incredibly uncomfortable since she and S* are good friends).
Essentially, I don’t know if I should let the situation alone or if I need to tell anybody else about what happened. I don’t think anyone is in any danger, physical or otherwise, but I worry about D*’s next girlfriend. He is very sweet and friendly at first, but then quickly transforms into the person I described above. He did so with me, he did so with S*, and I worry it will go farther with someone else. Then again, I have pretty much severed my connection with him. Also, again, to my knowledge, his behavior was never actually violent or physically threatening.
Thoughts?