Does allowing a police officer into your house implicitly waive your Fourth Amendment rights?
<p>Suppose a police officer knocks on your door and tells you there was a robbery in the neighborhood and asks if he can ask you some questions about it, but really what he wants is to collect evidence against you for an entirely different case.</p>

<p>You invite the officer into your house and answer his questions. Suppose there’s a drinking glass of yours in plain sight on the table. What he really wants is a sample of your DNA, so when you're not looking, he takes the glass.</p>

<p>Can the officer (or, more likely, lawyers for the prosecution) argue that this seizure was legal because you did invite the officer into the house (believing it to be for another reason)?</p>

<h2>Yes and No</h2>

<p>See <a href="https://www.law.cornell.edu/supremecourt/text/389/347" rel="noreferrer">Katz v. United States, 389 U.S. 347, 351 (1967)</a>:</p>

<blockquote>
  <p>What a person knowingly exposes to the public, even in his home or office, is not a subject of Fourth Amendment protection. But what he seeks to preserve as private, even in an area accessible to the public, may be constitutionally protected.</p>
</blockquote>

<p>The glass has clearly been "knowingly exposed" and if that glass was, on the normal methods of examination by the officer (sight, smell etc.), evidence of a crime then it would be able to be used as evidence. However, any DNA on that glass is not "knowingly exposed" - finding the DNA requires a laboratory, specialised equipment and trained technicians.</p>

<p><strong>Hard to Tell</strong></p>
<p>The individual consented to a search by letting the officer come in, and consent searches are held to be reasonable. Katz was an unconsented invasion of privacy (picking up sound through the glass in a telelphone booth). The glass has been &quot;knowingly exposed&quot;, and the glass is in plain sight (<a href="https://supreme.justia.com/cases/federal/us/496/128/" rel="noreferrer">Horton v. California</a>, 496 U.S. 128. &quot;The Fourth Amendment does not prohibit the warrantless seizure of evidence in plain view&quot;). One condition attaching to such seizures is that &quot;the officer must have a lawful right of access to the object itself&quot;, which derives from the consent. The other condition is that &quot;the object's incriminating character must be 'immediately apparent'&quot;. This later conclusion derives from <a href="https://supreme.justia.com/cases/federal/us/403/443/" rel="noreferrer">Coolidge v. New Hampshire</a>, 403 U.S. 443 which finds that &quot;the extension of the original justification is legitimate only where it is immediately apparent to the police that they have evidence before them&quot;.</p>
<p>Is it immediately apparent that a glass constitutes evidence? It is hard to imagine that DNA on a glass is itself evidence of a crime. DNA from a glass could provide the probable cause (given a match with crime-scene DNA) for a court-ordered collection of DNA from the person, and <em>that</em> DNA could be matched with the DNA found at the crime. But DNA from a glass in a house conjectured to be the DNA of the owner is not an admissible substitute for directly-collected evidence.</p>
<p>Is extraction of DNA itself a search? In some cases it is, see <a href="https://www.supremecourt.gov/opinions/12pdf/12-207_d18e.pdf" rel="noreferrer">Maryland v King</a>, where the court finds that</p>
<blockquote>
<p>using a buccal swab on the inner  tissues  of  a  person’s  cheek  in
order  to  obtain  DNA  samples  is  a  search</p>
</blockquote>
<p>with related citations. However, in some circumstances, such a body search is deemed reasonable, especially when the state needs to identify an individual under arrest (King). Things discarded in the trash may also be a search yet be permitted (<a href="https://supreme.justia.com/cases/federal/us/486/35/" rel="noreferrer">California v. Greenwood</a>, 486 U.S. 35), when the expectation of privacy is not reasonable.</p>
<p>In a current case (SD v. Bentaas), defense via <em>amici</em> <a href="https://www.eff.org/files/2020/03/10/amicus_brief_of_aclu_aclusd_eff.pdf" rel="noreferrer">is urging</a> that all DNA analysis constitutes a search, subject to Fourth Amendment protections. The argument that DNA contains vast amounts of personal information, and</p>
<blockquote>
<p>the extraction of an individual’s DNA sample and “the creation of his
DNA profile constitute[] a search for Fourth Amendment purposes.”
<a href="https://casetext.com/case/united-states-v-davis-204" rel="noreferrer">United States v. Davis</a>, 690 F.3d 226</p>
</blockquote>
<p>Amici also urge that the state has &quot;seized and has access to all of Ms. Bentaas’s genetic information as a result of the underlying DNA extraction&quot;. This case has the potential to have a substantial impact on DNA and the Fourth Amendment.</p>

<p>First, welcome to LSE, Josh. And congratulations on such a nice first question.</p>
<p>The answer to your question is <strong>No.</strong></p>
<p>Inviting an officer into your house to talk about a robbery does not give the officer the right to search your house. Talking and searching involve two different amendments, and you must waive your rights under each explicitly. However, under the <strong><a href="https://en.wikipedia.org/wiki/Plain_view_doctrine#:%7E:text=In%20the%20United%20States%2C%20the,view%20during%20a%20lawful%20observation." rel="noreferrer">plain view</a></strong> doctrine, police who are lawfully in your house can search (and seize) your property without a warrant if:</p>
<blockquote>
<p>a) the stuff they search or seize is in <strong>plain view</strong> (ie, “immediately apparent”); and,</p>
</blockquote>
<blockquote>
<p>b) they have <strong>probable cause</strong> to believe that whatever is in plain view contains evidence of a crime. (In other words, they can only search without a warrant if they could get a warrant, <em>based on what is in plain view.</em>)</p>
</blockquote>
<p>In your hypothetical, the police do not meet all of the requirements for a warrantless search under the plain view doctrine. They are there legally, and the glass is in plain view. However, the DNA is not in plain view, which means they will need to search the glass to find it. To search the glass, they need probable cause to believe that your DNA will link you to a crime.</p>
<p>In this case, the need for probable cause creates a catch-22 for the police. Because they can't get probable cause merely from looking at the glass, the police must have had probable cause to get your DNA before walked in your door. But if they had probable cause before they showed up, then the 4th Amendment requires them to get a warrant. The plain view rule does not allow the police to skip the warrant requirement for their own convenience.</p>
<p>To see how seizing the glass would require probable cause, consider <a href="https://supreme.justia.com/cases/federal/us/480/321/#tab-opinion-1957005" rel="noreferrer">Arizona v. Hicks</a>. In Hicks, police entered an apartment looking for a shooter. After finding the shooter, the police saw expensive stereo equipment that “seemed out of place in the squalid and otherwise ill-appointed four-room apartment.” Suspicious, they moved the stereo so they could read the serial number. When it turned out the stereo was stolen, they charged Hicks with theft. On appeal, the Court held that the serial number was not in plain view, and that seeming “out of place” did not establish probable cause to search the stereo. As a result, the search was unconstitutional.</p>

united-states search-and-seizure fourth-amendment