SB 1070, the Arizona “papers please” law held constitutional in part and unconstitutional in part and the court was concerned with lengthening detentions based on suspected illegal status without only a hunch. Arizona v. United States, first from the syllabus:

(c) By authorizing state and local officers to make warrantless arrests of certain aliens suspected of being removable, §6 too creates an obstacle to federal law. As a general rule, it is not a crime for a removable alien to remain in the United States. The federal scheme instructs when it is appropriate to arrest an alien during the removal process. The Attorney General in some circumstances will issue a warrant for trained federal immigration officers to execute. If no federal warrant has been issued, these officers have more limited authority. They may arrest an alien for being “in the United States in violation of any [immigration] law or regulation,” for example, but only where the alien “is likely to escape before a warrant can be obtained.” §1357(a)(2). Section 6 attempts to provide state officers with even greater arrest authority, which they could exercise with no instruction from the Federal Government. This is not the system Congress created. Federal law specifies limited circumstances in which state officers may perform an immigration officer’s functions. This includes instances where the Attorney General has granted that authority in a formal agreement with a state or local government. See, e.g., §1357(g)(1). Although federal law permits state officers to “cooperate with the Attorney General in the identification, apprehension, detention, or removal of aliens not lawfully present in the United States,” §1357(g)(10)(B), this does not encompass the unilateral decision to detain authorized by §6. Pp. 15–19.

Then from 22-23 of the opinion:

Some who support the challenge to §2(B) argue that, in practice, state officers will be required to delay the release of some detainees for no reason other than to verify their immigration status. See, e.g., Brief for Former Arizona Attorney General Terry Goddard et al. as Amici Curiae 37, n. 49. Detaining individuals solely to verify their immigration status would raise constitutional concerns. See, e.g., Arizona v. Johnson, 555 U. S. 323, 333 (2009); Illinois v. Caballes, 543 U. S. 405, 407 (2005) (“A seizure that is justified solely by the interest in issuing a warning ticket to the driver can become unlawful if it is prolonged beyond the time reasonably required to complete that mission”). And it would disrupt the federal framework to put state officers in the position of holding aliens in custody for possible unlawful presence without federal direction and supervision. Cf. Part IV–C, supra (concluding that Arizona may not authorize warrantless arrests on the basis of removability). The program put in place by Congress does not allow state or local officers to adopt this enforcement mechanism.

But §2(B) could be read to avoid these concerns. To take one example, a person might be stopped for jaywalking in Tucson and be unable to produce identification. The first sentence of §2(B) instructs officers to make a “reasonable” attempt to verify his immigration status with ICE if there is reasonable suspicion that his presence in the United States is unlawful. The state courts may conclude that, unless the person continues to be suspected of some crime for which he may be detained by state officers, it would not be reasonable to prolong the stop for the immigration inquiry. See Reply Brief for Petitioners 12, n. 4 (“[Section 2(B)] does not require the verification be completed during the stop or detention if that is not reasonable or practicable”); cf. Muehler v. Mena, 544 U. S. 93, 101 (2005) (finding no Fourth Amendment violation where questioning about immigration status did not prolong a stop).

To take another example, a person might be held pending release on a charge of driving under the influence of alcohol. As this goes beyond a mere stop, the arrestee (unlike the jaywalker) would appear to be subject to the categorical requirement in the second sentence of §2(B) that “[a]ny person who is arrested shall have the person’s immigration status determined before [he] is released.” State courts may read this as an instruction to initiate a status check every time someone is arrested, or in some subset of those cases, rather than as a command to hold the person until the check is complete no matter the circumstances. Even if the law is read as an instruction to complete a check while the person is in custody, moreover, it is not clear at this stage and on this record that the verification process would result in prolonged detention.

However the law is interpreted, if §2(B) only requires state officers to conduct a status check during the course of an authorized, lawful detention or after a detainee has been released, the provision likely would survive preemption—at least absent some showing that it has other consequences that are adverse to federal law and its objectives. There is no need in this case to address whether reasonable suspicion of illegal entry or another immigration crime would be a legitimate basis for prolonging a detention, or whether this too would be preempted by federal law. See, e.g., United States v. Di Re, 332 U. S. 581, 589 (1948) (authority of state officers to make arrests for federal crimes is, absent federal statutory instruction, a matter of state law); ...

Defendant’s stop was justified for following too close as corroborated somewhat by the video. A dog was immediately called in and conducted a sniff while the warning ticket was being filled out. The dog alerted within five minutes of the stop, so the stop was not prolonged. The officer’s testimony on the “well trained” dog was that the dog had 800 alerts with no false positives, so there was probable cause. United States v. Trejo, 2012 U.S. Dist. LEXIS 86740 (M.D. Fla. May 17, 2012).*

Defendant school teacher ordered a search of people in a room based on the smell of marijuana, but included plaintiff who she was aware arrived after the smell. The defendants were on notice that such a search was illegal under T.L.O. Plaintiff also stated a claim that the search was racially motivated against two African-American students who arrived after the smell. Doe v. Champaign Cmty. Unit 4 Sch. Dist., 2012 U.S. Dist. LEXIS 86857 (C.D. Ill. February 24, 2012).*

Orin S. Kerr, The Mosaic Theory of the Fourth Amendment, 110 Mich. L. Rev. ___ (2012), on SSRN. Abstract:

In the Supreme Court’s recent decision on GPS surveillance, United States v. Jones (2012), five Justices authored or joined concurring opinions that applied a new approach to interpreting Fourth Amendment protection. Before Jones, Fourth Amendment decisions have always evaluated each step of an investigation individually. Jones introduced what we might call a “mosaic theory” of the Fourth Amendment, by which courts evaluate a collective sequence of government activity as an aggregated whole to consider whether the sequence amounts to a search.

This article considers the implications of a mosaic theory of the Fourth Amendment. It explores the choices and puzzles that a mosaic theory would raise, and it analyzes the merits of the proposed new method of Fourth Amendment analysis. The article makes three major points. First, the mosaic theory represents a dramatic departure from the basic building block of existing Fourth Amendment doctrine. Second, adopting the mosaic theory would require courts to answer a long list of novel and challenging questions. Third, courts should reject the theory and retain the traditional sequential approach to Fourth Amendment analysis. The mosaic approach reflects legitimate concerns, but implementing it would be exceedingly difficult in light of rapid technological change. Courts can better respond to the concerns animating the mosaic theory within the traditional parameters of the sequential approach to Fourth Amendment analysis.

The seizure of defendant’s cell phone was with probable cause because he was a suspect in a murder. The police did not search it until they obtained a warrant consistent with Smith. The seizure of the telephone was not inconsistent with Smith. Under Segura, a seizure and search protect different interests, but they both have to be justified. This was. State v. Cunningham, 2012 Ohio 2794, 2012 Ohio App. LEXIS 2443 (2d Dist. June 22, 2012):

[*P28] The police did not search the contents of Defendant's cell phone at issue until after a search warrant was obtained to search those contents. Defendant does not challenge the validity of the search warrant but instead argues that the seizure of the cell phone itself without a warrant required the trial court to exclude all evidence derived from the cell phone after the search warrant was issued pursuant to the Supreme Court's decision in Smith. We do not agree.

[*P29] The police had identified Defendant as a key suspect in a double homicide that occurred only hours before Defendant was sitting in the interview room. (Motion to Suppress Tr., p. 7-10.) Defendant was at police headquarters for purposes of an interview concerning those crimes and used the phone while waiting to be interviewed. Defendant's phone was confiscated by police out of a concern that relevant information memorialized on the phone would be deleted or lost. At no point between the time that Detective Baader seized Defendant's cellular phone and the time when the search warrant was issued did the police search the records stored inside Defendant's phone. (Id. at 15, 25, 39, 42, 46, 50.)

[*P30] The police had probable cause to seize Defendant's cellular phone until a search warrant could be obtained. As the Supreme Court recognized in Smith, the police had an "immediate interest in collecting and preserving evidence and can take preventive steps to ensure that the data found on the phone are neither lost nor erased." Smith, ¶ 23. The confiscation of Defendant's phone did just that.

Nervousness and claiming to have flown from Texas to San Francisco to rent a Mercedes to drive to Chicago for no apparent reason was reasonable suspicion of drug trafficking. Phelps v. State, 2012 WY 87, 278 P.3d 1148 (2012).*

U.S. Court of Federal Claims has no jurisdiction over Fourth Amendment claims against the government. Cox v. United States, 105 Fed. Cl. 213 (2012) [for the 1000th time].

Plaintiff’s Fifth Amendment claims about animal welfare seizure were precluded by a state court action under the Rooker-Feldman doctrine. Her Fourth Amendment claims, however, predated the state court judgment and were not precluded, despite the fact the state court even considered the search and seizure claim. The Fourth Amendment claim may be precluded, but not under the district court’s analysis and more development of the record is required. Campbell v. City of Spencer, 682 F.3d 1278 (10th Cir. 2012).*

Defendant’s frisk for “generalized safety” was not shown to have any lawful basis, and the motion to suppress should have been granted. The state confessed error. State v. Brooks, 2012 Tenn. Crim. App. LEXIS 425 (June 20, 2012).*

Officers came to defendant’s house with an attachment order for failure to pay child support. The officer was invited inside and then the occupants consented to a search which was shown to be voluntary. State v. Dixon, 2012 Tenn. Crim. App. LEXIS 423 (June 21, 2012).*

The officer here saw defendants smoking marijuana at a Wendy’s so he followed them, stopped them for a traffic offense and smelled more. A search warrant for their motel room was issued, and it was with probable cause and nexus. United States v. Taylor, 471 Fed. Appx. 499 (6th Cir. 2012).*