# Cops leaving fingerprints as evidence **URL:** \ **Category:** In My Humble Opinion\ **Created:** [April 25, 2025, 5:04pm UTC](https://boards.straightdope.com/t/cops-leaving-fingerprints-as-evidence/1017490 "2025-04-25T17:04:14Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Lucas\_Jackson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lucas_jackson/32/303_2.png) [@Lucas\_Jackson](https://boards.straightdope.com/u/Lucas_Jackson)\ **Post date:** [April 25, 2025, 5:04pm UTC](https://boards.straightdope.com/t/cops-leaving-fingerprints-as-evidence/1017490/1 "2025-04-25T17:04:14Z")
[In this video (high speed car chase stop),](https://www.youtube.com/watch?v=A4rh6EqbYfU) starting at 4:00, the officer touches the tail light to “leave physical fingerprint evidence in case the encounter turns deadly”. Huh? I’ve never heard of this. Wouldn’t the video itself be proof the officer was there? Or even, the officers dead body? Can someone shed more light on this for me, thanks. ---
**Author:** ![Saint\_Cad](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saint_cad/32/18907_2.png) [@Saint\_Cad](https://boards.straightdope.com/u/Saint_Cad)\ **Post date:** [April 25, 2025, 5:15pm UTC](https://boards.straightdope.com/t/cops-leaving-fingerprints-as-evidence/1017490/2 "2025-04-25T17:15:14Z")
If he is killed by the driver and later they find the car, they can show that the cop had stopped THAT car. Told to me by my deputy uncle. ---
**Author:** ![Lucas\_Jackson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lucas_jackson/32/303_2.png) [@Lucas\_Jackson](https://boards.straightdope.com/u/Lucas_Jackson)\ **Post date:** [April 25, 2025, 5:18pm UTC](https://boards.straightdope.com/t/cops-leaving-fingerprints-as-evidence/1017490/3 "2025-04-25T17:18:14Z")
Ah, OK, I guess that makes sense. Weird I’ve never heard of such a thing. ---
**Author:** ![hajario](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hajario/32/171_2.png) [@hajario](https://boards.straightdope.com/u/hajario)\ **Post date:** [April 25, 2025, 5:20pm UTC](https://boards.straightdope.com/t/cops-leaving-fingerprints-as-evidence/1017490/4 "2025-04-25T17:20:40Z")
It’s common ish knowledge. I’ve heard it referenced a lot and may have learned about it here. ---
**Author:** ![jnglmassiv](https://avatars.discourse-cdn.com/v4/letter/j/f07891/32.png) [@jnglmassiv](https://boards.straightdope.com/u/jnglmassiv)\ **Post date:** [April 25, 2025, 5:36pm UTC](https://boards.straightdope.com/t/cops-leaving-fingerprints-as-evidence/1017490/5 "2025-04-25T17:36:14Z")
It’s also said to ensure the trunk or hatch is latched. ---
**Author:** ![thorny\_locust](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thorny_locust/32/431_2.png) [@thorny\_locust](https://boards.straightdope.com/u/thorny_locust)\ **Post date:** [April 25, 2025, 7:29pm UTC](https://boards.straightdope.com/t/cops-leaving-fingerprints-as-evidence/1017490/6 "2025-04-25T19:29:46Z")
> [@hajario](#): > > It’s common ish knowledge. If it’s common ish knowledge, isn’t there a significant chance that the people in the car will know to wipe off the fingerprints? ---
**Author:** ![Alessan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alessan/32/465_2.png) [@Alessan](https://boards.straightdope.com/u/Alessan)\ **Post date:** [April 25, 2025, 8:46pm UTC](https://boards.straightdope.com/t/cops-leaving-fingerprints-as-evidence/1017490/7 "2025-04-25T20:46:50Z")
> [@thorny\_locust](#): > > If it’s common ish knowledge, isn’t there a significant chance that the people in the car will know to wipe off the fingerprints? Sure, but there’s also a significant chance that they won’t. ---
**Author:** ![hajario](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hajario/32/171_2.png) [@hajario](https://boards.straightdope.com/u/hajario)\ **Post date:** [April 25, 2025, 9:20pm UTC](https://boards.straightdope.com/t/cops-leaving-fingerprints-as-evidence/1017490/8 "2025-04-25T21:20:06Z")
Definitely. I would think they would. ---
**Author:** ![Loach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/loach/32/350_2.png) [@Loach](https://boards.straightdope.com/u/Loach)\ **Post date:** [April 25, 2025, 9:59pm UTC](https://boards.straightdope.com/t/cops-leaving-fingerprints-as-evidence/1017490/9 "2025-04-25T21:59:37Z")
It’s one of those things that one field training officer thought was a good idea at the time and it spread. When asked if it was ever useful in any actual case you get a lot of silence. The two usually cited reasons to do it have been replaced by technology. Leaving evidence behind- body and vehicle cameras. Someone popping out of a partially opened trunk- trunk and hatch releases. I stopped doing it soon after I got out of the academy because it was dumb.