Amazon’s Alexa and Apple’s Siri are among some of the seemingly countless AI technological advances that have made our lives easier and more streamlined – but our devices are also collecting data that could one day be used as digital evidence against us in court.

In the CLE program Search and Seizure in the Digital Realm, digital forensic expert Brian Chase explains the key Supreme Court cases involving Fourth and Fifth Amendment rights that apply to digital evidence. We’ve compiled the top questions attorneys should raise when challenging warrants for digital evidence in court. Check them out below:

1. Was There a Reasonable Expectation of Privacy?

If the data gathered went beyond the scope of a warrant that was issued, the use of that data may constitute a trespass, and may have impeded on a defendant’s reasonable expectation of privacy. In United States v. Jones, law enforcement put a GPS device in the defendant’s vehicle and monitored his movement for a month. The GPS device was not installed within the timeframe specified by the warrant, nor was the device installed within the location specified by the warrant. The warrant was found to be invalid and, in the majority opinion, Justice Scalia indicated that the warrantless search was a violation of Jones’ Fourth Amendment right, constituting a trespass. In his concurring opinion, Justice Alito also brought up a reasonable expectation of privacy argument that use of longer-term GPS monitoring in investigations of most offenses, beyond four weeks, impinges on one’s expectations of privacy.

2. How Much Data Collection Did the Warrant Allow?

A warrant must describe with particularity what data is to be collected – a general search and seizure will not stand. In Riley v. California, Riley’s cellphone was searched without a warrant. The Supreme Court ruled that a warrant is required to search a cell phone, and that the data to be collected must also be specified in light of the excessive amount of data stored in cell phones, and the probable cause requirement for a search by law enforcement. Even if the “plain view” doctrine is evoked, data from cell phones may not be considered in plain view because Cellebrite, the program most law enforcement agencies use to download phone content, requires selection of specific data to download and, therefore, that data is not actually in plain view.

3. Does the Third-Party Doctrine Apply?

Under the third-party doctrine, if a person voluntarily provides information to a third party (like the phone company, for example), the Fourth Amendment typically does not preclude the government from accessing it without a warrant because a person has “no legitimate expectation of privacy” in that data. Carpenter v. United States raised the possibility that a warrant may be required for other kinds of records like online accounts, modern bank records, or smart devices to abide by a person’s Fourth Amendment rights. In Carpenter, law enforcement obtained 127 days’ worth of historical cell site location information under the Stored Communications Act. The Supreme Court ruled that a warrant is required for information spanning a length of time of 7 days or more and declined to use the third-party doctrine.

4. Are the Passwords Protected?

The Fifth Amendment provides an individual protection against being “compelled in any criminal case to be a witness against himself.” Passwords, which are an expression of the contents of an individual’s mind, fall squarely within the protections of the Fifth Amendment. For devices that are unlocked via fingerprint, the Eighth Circuit has found fingerprints to be non-testimonial evidence, but producing a fingerprint can communicate possession or control of the device as testimonial evidence. Nevertheless, even if a fingerprint is obtained to unlock a phone, a password is still needed to download the contents of the phone.

5. Can the Prosecution Rely on the Search as Being Done in “Good Faith”?

Exclusionary rules prevent the government from using certain evidence gathered in violation of the United States Constitution. Exclusionary rules vary from jurisdiction to jurisdiction but, as indicated in Davis v. United States, searches conducted in objectively reasonable reliance on binding appellate precedent are not subject to the exclusionary rule.

To learn more about digital evidence and the Constitution, check out the full program here.

Related Content:

1. Using Location Data in Litigation: From Cell Phone to Cell Towers and Smart Homes
2. Constitutional Rights at the Border: Digital Device Searches & Related Issues
3. Electronic Information in Criminal Proceedings: 4th & 5th Amendment Implications

This post was prepared with the assistance of Elsie Tan, a New York Law School student.