Searching vehicles, phones and digital devices

Desjardins holds up two objects: a set of car keys and a phone. 'Twenty years ago,' he says, 'most of the evidence I seized in a year came out of cars and houses. Today, most of it comes out of one of these,' and he holds up the phone. 'And the car keys now unlock a computer on wheels that records where it has been, how fast it went and who it was connected to.' Vehicles and digital devices are where search law has changed fastest, and where officers most need to know the current rules. This lesson brings together what the class has already learned about warrants, search incident to arrest and the exceptions, and applies it to the two places officers search most often.

Vehicles: a lower but real expectation of privacy

The Supreme Court has long treated vehicles differently from homes. Under the automobile exception, which began with Carroll v. United States (1925), officers who have probable cause to believe a vehicle contains contraband or evidence of a crime may search it without a warrant, anywhere in the vehicle where the object of the search could be. United States v. Ross (1982) extended this to containers in the car, and California v. Acevedo (1991) to a container placed in the car for which police had probable cause. The rationale is the car's ready mobility and the reduced expectation of privacy on public roads. The exception does not apply to a car parked within the curtilage of a home, as Collins v. Virginia (2018) held. Separately, Arizona v. Gant (2009) limits searches incident to arrest, and Michigan v. Long (1983) allows protective sweeps of the passenger area during a stop when the officer reasonably believes the suspect is dangerous.

In practice, this means a American officer at a vehicle stop must ask a specific question before looking inside: under which power am I searching? If the answer is the automobile exception, the officer needs probable cause that evidence or contraband is in the car. If it is a search incident to arrest, Gant's conditions must be met. If it is consent, it must be voluntary. And if the answer is 'I just wanted to see,' there is no power, and anything found is likely to be excluded.

Inventory searches and impounds

When police lawfully take custody of a vehicle, for instance after an arrest or when it is towed from a dangerous position, they may list its contents to protect the owner's property, protect police from false claims, and protect officers from hazards. In South Dakota v. Opperman (1976) and Colorado v. Bertine (1987), the Supreme Court upheld inventory searches conducted under standardized police procedures, and in Florida v. Wells (1990) it held that an inventory search without a standard policy governing the opening of containers was unlawful. The key is that the impound must be lawful and the inventory must follow a written policy, applied the same way every time.

Phones: the normal route is a warrant

Phones are the most important source of evidence in modern investigations and the most sensitive. LES-111 covered the constitutional principles and Lesson 7 covered search incident to arrest. Here Desjardins focuses on the practical workflow that keeps a phone's evidence admissible. In the United States, Riley requires a warrant to search the data on a phone seized incident to arrest, absent exigency, and the same is true for phones seized in other circumstances. In Carpenter v. United States (2018), the Supreme Court held that obtaining seven days or more of historical cell-site location records from a phone company is a search requiring a warrant, despite the third-party doctrine. Federal and state courts have since applied similar reasoning to other digital records. Ohio practice is for officers to seize the phone, secure it against remote wiping, and apply for a warrant describing the data sought.

The workflow Desjardins teaches has five steps. First, seize the phone lawfully, under search incident to arrest, a warrant, plain view or consent. Second, secure it: photograph it, note whether it is on or off and locked or unlocked, and place it in a signal-blocking bag or airplane mode only if trained to do so, because some actions can change data. Third, document the chain of custody from the moment of seizure. Fourth, apply for a warrant that describes the device, the data types and the time period sought, and explains why those data are likely to hold evidence. Fifth, have a trained examiner extract and analyze the data within the warrant's terms, keeping a record of what was examined. A warrant that asks for everything on the phone for all time is likely to be found overbroad; one that asks for messages, photos and location data between two dates connected to the offense is much stronger.

# Is a phone warrant request focused? Compare the requested window to the crime timeline.
from datetime import date
crime_start = date(2026, 3, 1)     # earliest planning evidence
crime_end = date(2026, 3, 20)      # date of the garage search
requested = {"messages": (date(2026, 3, 1), date(2026, 3, 20)),
             "photos": (date(2026, 3, 1), date(2026, 3, 20)),
             "location": (date(2026, 3, 13), date(2026, 3, 15)),
             "browser history": (date(2020, 1, 1), date(2026, 3, 20))}
for kind, (a, b) in requested.items():
    days = (b - a).days + 1
    outside = max(0, (crime_start - a).days) + max(0, (b - crime_end).days)
    flag = "focused" if outside == 0 else f"{outside} days outside the crime period"
    print(f"{kind:16} {days:5} days  {flag}")

messages            20 days  focused
photos              20 days  focused
location             3 days  focused
browser history   2271 days  2251 days outside the crime period

Three of the four requests are tied closely to the offense period. The browser history request covers more than six years, almost all of it before any evidence of planning. Detective Sergeant Ali's supervisor sent that part back and asked him to justify a longer window or narrow it. He narrowed it to the same period as the messages. A reviewing judge, Desjardins says, would almost certainly have asked the same question, and a warrant that is overbroad in part can lead a court to question the whole thing.

Unlocking devices and passwords

Locked phones raise their own questions. Courts are divided on whether compelling a person to provide a passcode violates the Fifth Amendment privilege against self-incrimination, and on whether compelled biometric unlocking such as a fingerprint or face scan is treated differently. Officers should not compel a passcode without legal advice; a warrant can authorize forensic examination, and officers can ask for voluntary cooperation after proper warnings. Desjardins tells the class that forensic tools can open many devices, but not all, and that a voluntary unlock, properly recorded, is still valuable.

Other devices: computers, vehicles and cloud data

The same principles apply to laptops, tablets, game consoles and smart watches. Modern vehicles carry infotainment systems that record paired phones, call logs, locations and even text messages, and event data recorders that store speed and braking information before a crash. Data stored in the cloud may be held by a company in another country. Each of these needs lawful authority, and in most cases that means a warrant or court order or warrant directed to the provider. Desjardins describes a Port Ardent collision investigation where the event data recorder showed a driver at 112 km/h in a 50 zone two seconds before impact, evidence obtained under a warrant that specified exactly which modules would be downloaded.

Vehicle searches at the roadside: a practical checklist

Desjardins finishes the vehicle section with a checklist for officers at the roadside. Know why you stopped the vehicle, and stay within that purpose unless new grounds arise. Identify the power before searching: probable cause, arrest under Gant, consent or warrant. Search only where the item could be. Record what you searched and why, what you found and where. If the car is impounded, follow the inventory policy exactly. And if the phone in the cupholder might hold evidence, seize and secure it, and leave the screen alone until a warrant says otherwise.

Border and regulatory searches

Some searches of vehicles and devices happen under powers that have little to do with criminal investigation. At the border, Customs and Border Protection officers may search vehicles and goods without a warrant or suspicion, under the long-recognized border search exception, and federal courts have divided on whether and when a forensic search of a phone or laptop at the border requires reasonable suspicion. Municipal police rarely use these powers, but officers working on joint task forces or near a border crossing should know they exist and that they belong to other agencies.

Regulatory searches are another category. Commercial vehicle inspections, liquor license inspections of bars, and inspections of scrap metal dealers and pawnshops are authorized by statutes that set their own conditions, often allowing inspection without a warrant during business hours for regulatory purposes. Police may sometimes accompany inspectors, but they cannot use a regulatory inspection as a way around the warrant requirement for a criminal investigation. Once the purpose shifts from checking compliance to gathering evidence of a crime, the criminal rules apply.

Desjardins gives an example from Port Ardent. Officers checking a pawnshop's register under the municipal licensing bylaw found a listing for a cordless drill whose serial number matched one of the items stolen from Lakeshore Hardware. They could note the entry under the bylaw, but to seize the drill as evidence and examine the shop's records for other stolen goods, they obtained a warrant. The drill turned out to have been pawned by a man who had bought it from Brandt, which added a charge of trafficking in stolen property to the file.

Priya Sandhu, who spent five years investigating fraud at a bank, adds a point from her own experience: much of the most useful evidence about a person's movements and money is held by companies, not on the person's own devices. Bank records, ride-share trips, toll records and app data can all be obtained with the right court order, and they are often more complete and more reliable than what is on a phone. Desjardins agrees and tells the class that a good investigator thinks about where evidence is held before deciding which power to use, and that the order to a company is often both more effective and less intrusive than a search of the person's device.