Chief Stone makes a traffic stop on a car that has been following him. The driver pulls off his sunglasses and sets them on the dash. Then Chief Stone approaches the driver's door and asks for license and registration. The sunglasses are back on so the driver pulls them off and sets them on the dash a second time.
On the night that Jessie gets his job back, there is a thunderstorm and rain can be seen running down the closed window. Later, there is a shot of the ocean with what would seem to be a ray of the full moon shinning on it. The next morning, Jessie is awakened with sunshine on his face and the curtains can be seen blowing in the wind from the open window.
The Massachusetts automobile inspection sticker is on the wrong side of the windshield. The sticker has been on the right (passenger) side of the windshield since at least 1960.
During the scenes on the ship, Jesse Stone fires his Colt M1911 nine times before reloading. The magazine of the M1911 holds seven rounds. Further more, when Jesse changes magazines, there's at least one round left in the original magazine. He would not have changed magazines after the first four shots, knowing he would have three rounds left as well as he's very close to the man he's after, risking being exposed not ready and the sound would have revealed his position.
When the Chief's car is engulfed in flames you can see the flames through the front grill and tell there is no engine in the engine compartment.
When Officer D'Angelo is driving Chief Butler, before the explosion, you can briefly see a 70 mph speed limit sign. There are no posted 70 mph speed limits on Massachussetts rural roads. It's a Canadian 70 kilometer per hour (43.50 mph) sign.