Can a lens kill a 5D?

I have a new 5D, and it has just completely died for the second time.

The first time I got it fixed by Canon. They said the power circuit had died.

Both times it happened the moment I mounted an old Tokina 28-210 3.5-5.6. I was trying to do test shots with different lenses, and the other lenses I managed to test before the camera died worked fine (16-35 2.8 L, 28 1.8, 50 1.8 II, all Canon). The Tokina works fine on my Digital Rebel.

So now, after having just got it back from Canon, I have a dead 5D on my hands again, and not very happy about it.

Can a lens break a camera? It seems hard to believe that Canon wouldn't have engineered circuit protections into the camera to deal with anything a lens might throw at it.

Does anyone else have experience with this? I spent a good bit of time searching and haven't been able to find any information online.