The Fourth Amendment does not allow law enforcement to fish around in people’s electronic devices to see if they can find evidence of a crime. Instead, they must have a warrant describing the device to be searched and the particular evidence they may search for. It usually is not feasible to search a computer or other device on the spot, seize only the relevant files, and take those files back to the station – the way police would execute a search warrant of a file cabinet, for example. Instead, warrants sometimes allow police to seize a device and then conduct a forensic search for the type of evidence described in the warrant.
We filed an amicus curiae brief in the Illinois Supreme Court in People v. McCavitt, a case about the limits on law enforcement’s authority to search a device under such a warrant.
In 2013, the Illinois State Police obtained a warrant to search John McCavitt’s home and seize his computer, then received another warrant. Later they received a warrant to search the computer for evidence of certain sexual offenses against a particular victim. The Peoria County Sheriff’s made an exact copy of the computer hard drive and searched the copy for the evidence described in the warrant. In 2014, Mr. McCavitt was charged with two counts of sex offenses based on evidence found on the hard drive. The jury acquitted him of both charges.
The day after Mr. McCavitt’s acquittal, the Peoria Police Department—Mr. McCavitt’s employer—requested the copy of his hard drive from the Sheriff. Without getting a new warrant, the police searched the drive for evidence of other crimes against other victims. Finding some pictures that they thought looked like child pornography, the police then obtained a search warrant to look for further images of child pornography. As a result, Mr. McCavitt was charged and convicted of possession of child pornography.
Mr. McCavitt appealed, arguing that the Peoria Police Department unlawfully searched the information on his hard drive for new information without a new warrant, after the evidence found under the first warrant was insufficient to convict him. The Illinois Appellate Court agreed, and the State appealed to the Illinois Supreme Court.
The State claims that the Peoria Police Department simply took a “second look” at evidence that was lawfully in the government’s possession and had already been lawfully searched pursuant to a valid warrant. Our amicus brief refutes the State’s specious reasoning. Although the government had a copy of Mr. McCavitt’s entire hard drive, its warrant only entitled it to search for certain evidence of a particular crime. The government could look at the evidence it found under the warrant as many times as it liked. But it could not look for new evidence in the hard drive of crimes that were not described in the original warrant.