In United States v. Finley, 477 F.3d 250 (5th Cir. 2007), the Fifth Circuit Court of Appeals ruled that law enforcement officers may search cell phones incident to a lawful arrest.
Citing both United States v. Robinson, 414 U.S. 218 (1973) and New York v. Belton, 453 U.S. 454 (1981), the Court stated “Police officers are not constrained to search only for weapons or instruments of escape on the arrestee’s person; they may also, without any additional justification, look for evidence of the arrestee’s crime on his person in order to preserve it for use at trial.” Finley at 259-260.
Finley was charged with and ultimately convicted of aiding and abetting possession with intent to distribute a controlled substance (methamphetamine). After his arrest and during the search of his cell phone, law enforcement officers found incriminating text messages relating to drug trafficking which were used against him at his trial.