The movie ends with Professor Gramm speaking on the phone to Jon Foster and telling him that he's just got 12 hours to live, mimicking the menacing tone he's been given throughout the movie. Some copies of the film end there, while in some DVD versions, there is a scene afterwards in which Professor Gramm tells his class that Forster was killed via lethal injection.
There are at least two BluRay versions that end with Jack telling Forster he has 12 hours to live. So both without the scene afterwards about Forsters death. The run times of these two versions differ by several minutes (~1:47 vs ~1:51). In the longer version, while some scenes are actually cut drastically, many other scenes contain a lot of extra dialogue. The differences in scenes are thus bigger than the differences in runtime.