Look out, because this post includes season-ending spoilers! From Alias!
So in the last moments of the show, just as Alias's fianc? is in the middle of a totally awesome season-ending revelation, they get hit by a car. It's super-fast -- from "whoa there's a car" to impact in about 4 frames. Using TiVo to take a closer look at those frames, we discover that the car in question is a Ford Explorer. Not at all unlike the ones that come standard issue from CTU. The ones you might see driven by...
...24's Jack Bauer.
Coincidence? No, stupid! Obviously, Jack met up with Alias's mom (because they both had to travel the countryside as fugitives, and you end up meeting a lot of people that way. They probably ran into the Incredible Hulk, too.) Naturally they hit it off. And, um...obviously for some reason they decided to kill Alias and her fianc?. Well, I haven't worked out all the details yet. But it was Jack for sure!!