The Supreme Court last week ruled that pulling cellular site records from a wireless carrier requires law enforcement to obtain a warrant, a potentially far-reaching decision for the telecom industry,

In ruling 5-4 on the side of Timothy Carpenter, who was convicted in 2013 of robbing Radio Shack and T-Mobile stores, the court determined that law enforcement officers illegally procured location data from his cell phone carriers. The government was able to get 12,898 location points tracking Carpenter over 127 days, with four of those hits putting Carpenter near sites where robberies had occurred.

The court said that collecting cell site location information (CSLI) constituted a Fourth Amendment search and should have required a warrant. Chief Justice John Roberts, who wrote the majority opinion, said "modern cell phones generate increasingly vast amounts of increasingly precise CSLI.”

The decision in Carpenter v. United States could lead to a flood of litigation by defendants in pending criminal cases, challenging whether CSLI data can be used against them if a warrant wasn't issued.

“The main issue is what type of legal process the government needs to obtain location data," said Hanley Chew, a privacy and security lawyer at Fenwick & West LLP, in Mountain View, California. "With the Carpenter decision, it is definitive that they have to meet the higher burden of obtaining a warrant for that type of information.”