L.A. Noire
60 Achievements
Not So Hasty
Stop a fleeing suspect with a warning shot as an LAPD Detective.
How to unlock the Not So Hasty achievement in L.A. Noire - Definitive Guide
Once it fills, a cutscene will play out and you should get the achievement. It is important to note that you must not manually shot the suspect yourself as that will not work.
If you mess up, you can simply catch up to him and let him shoot the innocent civilian that he holds hostage in order to restart the checkpoint. It will say "case failed" but I didn't notice that it has any sort of affect on a 5 star case rating. The achievement will unlock after the ending cutscene when properly executed.
GameGod03's suggestion is good, but in case you missed that one, you have at least two more opportunities.
*The Gas Man case. Where you want to talk to Reginald Varley, but he runs off. It's in the Elysian Field area, so there is a lot of space to fire a warning shot.
*The Daylight Robbery crime case in Vice. Some guy shoots his revolver empty after a failed robbery of a liquor store and flees. If you keep him in your aiming sights, Phelps will fire a warning shot to stop him.
However, unlike the solution above there is a place a lot earlier in the episode
The achievement will pop a few seconds after the animation and the gave autosaves
Cases: A Marriage Made In Heaven [Traffic] & The Gas Man [Arson].
Street Crimes: Masked Gunman [Traffic], Running Battle [Homicide], Misunderstanding [Homicide] & Daylight Robbery [AD Vice].
This achievement is a little more tricky than the others. Again you'll need a fleeing suspect but in most cases or street crimes, you won't have your gun out to fire off a warning shot.
Firing a warning shot can be done in a few cases or street crimes, so play through until your suspect makes a run for it and you have your gun in hand as you chase after them. To pull off a warning shot you need to make sure your suspect is on a straight running path as this makes it easier.
Once everything is lined up, hold and aim your reticle dot at your suspect. You'll then notice a circle will form and start to fill up. Make sure you don't move your reticle off the suspect otherwise the circle will reset. Once the circle has been filled, Cole will fire the warning shot automatically and your suspect will halt in his tracks!
Case/s: A Marriage Made In Heaven [Traffic] & The Gas Man [Arson].
Street Crime/s: Masked Gunman [Traffic], Running Battle [Homicide], Misunderstanding [Homicide] & Daylight Robbery [AD Vice].
This achievement is a little more tricky than the others. Again you'll need a fleeing suspect but in most cases or street crimes, you won't have your gun out to fire off a warning shot.
Firing a warning shot can be done in a few cases or street crimes, so play through until your suspect makes a run for it and you have your gun in hand as you chase after them. To pull off a warning shot you need to make sure your suspect is on a straight running path as this makes it easier.
Once everything is lined up, hold and aim your reticle dot at your suspect. You'll then notice a circle will form and start to fill up. Make sure you don't move your reticle off the suspect otherwise the circle will reset. Once the circle has been filled, Cole will fire the warning shot automatically and your suspect will halt in his tracks!
There are times where Cole will have to apprehend a suspect alive, this will be the time where Cole will take out his weapon and you will have to aim down the suspect. Once your cross-hair is on the suspect you will see a meter start to fill the circle; it fills up Clockwise. Once the meter is filled, a short cutscene will happen and Cole will shoot one in the air, stopping the fleeing suspect. You can do this in most street crimes you do or later in the game on a story case. You will get a chance to try this out when you are a Patrolman.
Helpful hint: A side mission that suits this trophy perfectly is the "Daylight Robbery" mission available during the first ad vice case: Thank you dz06lt for the tip.
YouTube - L.A. Noire: Not So Hasty Achievement Guide
Video example