After Jake is attacked by the white dog that belonged to Gloria, he is shown with a big blood stain on his shirt and a bandage on the left side of his neck. The following day/days later, there is no sign of an injury or bandage on his neck.
When Sam and Jake are in the "acting Class" Sam stands up to stop the "teacher" from picking on Jake. Sam picks up his gear bag and they go towards the door, but a few seconds before, the row of chairs that are in front of Sam didn't have anything on them.
The Indian had used an auger bit to open the victim's safe, and eventually to kill her. An auger bit was used because of their aggressive look, but would have no affect on a steel safe. They are for wood.
The first time Jake spots Gloria through the telescope he watches her for a moment, then she moves across the room. Jake is then shown turning the telescope a couple of inches to follow her movement. From his distance, a couple inches would have been much too far too keep her view.
When Jake is being interrogated by the detective, the detective initially says that he has a problem with Jake because Jake is the only witness to the murder. Later in the interrogation, the detective says that he can not hold Jake because he has witnesses to back up Jake's story.