The Supreme Court signaled Wednesday it could impose limits on the government's ability to track Americans' movements through collection of their cellphone information.

The justices heard 80 minutes of arguments in a case at the intersection of privacy and technology.

Chief Justice John Roberts and the court's four liberal justices indicated they could extend the Constitution's protection against unreasonable searches to police collection of cellphone tower information that has become an important tool in the investigation of crimes.

In the case before the court, investigators acquired 127 days of cellphone tower information without a search warrant that allowed them to place Timothy Carpenter in the vicinity of a string of robberies of Radio Shack and T-Mobile stores in Michigan and Ohio. Carpenter is serving a 116-year prison term for his role in the robberies.

"The whole question is whether the information is accessible to the government" without a warrant, Roberts said. Investigators were able to get the cell tower records with a court order that requires a lower standard than the probable cause, or strong evidence that a person has committed a crime, that police must show to get a warrant.

Underlying the argument was some justices' wariness of new technology and its ability to track not just movements, but purchases, subscriptions, internet searches and every aspect of Americans' lives.