Can the police gather fingerprints and/or DNA for &quot;exclusionary&quot; purposes without a warrant or arrest?
<p>Occasionally on police procedurals some well-meaning or otherwise bystander disturbs the <em>absolute sanctity</em> of a crime scene before Our Heroes&trade; can perform a CSI montage. They might be accosted and asked to provide prints/DNA for "exclusionary" purposes, so any fingerprints found can be identified as the bystander versus an unknown suspect.</p>

<p>Can the police obtain these without consent (without an arrest)? If they are provided (consensually or otherwise) are they at risk of being added to some (criminal) database?</p>

<p>You give no jurisdiction but in general:</p>

<p>First, police have no obligation to be honest.</p>

<p>So, yes they can collect this without consent by e.g. taking hair from your hairbrush (with a warrant) or giving you a glass of water while interviewing you and getting it from your fingerprint oils (which may not actually be technically possible but never mind that). No, they can't take it by "force" by sticking a swab in your mouth.</p>

<p>Yes, it will almost certainly go into a database.</p>

<p>Of course, there are some jurisdictions where police are entitled to decide you are guilty based on the fact that you didn't pay them a bribe.</p>

privacy police evidence