Alexa Bartell murder: Warrants to search phone company data were crucial in rock throwing arrests

A week after the tragic rock-throwing murder of Alexa Bartell, three suspects sat inside the Jefferson County jailhouse with the help of information gathered from a search for cellphones. 

"This really came as a result of cellphone device forensics. And then supporting information from our public," said Jefferson County Sheriff spokeswoman, Jacki Kelley.

Three young men, Nicholas Karol-Chik, Zachary Kwak and Joseph Koenig, each listed as 18 years old, were taken into custody. 

Searching for cellphones in a given area is called geofencing. The department issued warrants for information from cellphone companies that helped them hone in on the suspects. 

"Some people call it a reverse warrant. Because with regular warrants usually, we know what we're looking for," said veteran attorney, Karen Steinhauser, who has worked as both a prosecutor and defense attorney. 

By asking for data on what phones were in a particular area, investigators can look for patterns, like which phones showed up at multiple crime scenes. 

"The idea is then that the police take those and do their own research with that information to try to narrow down the particular phones and then be able to request more specific detailed information," she said. 

Typically, they won't ask for identifying information until they find phones they want to focus on.

Questions about civil liberties have risen over the searches. As a relatively recent investigative technique in the age of cellular phones. It is hardly settled law says Steinhauser. 

But as phone users, we have often already been granted permission for sharing information on where we are. 

"We're giving permission to a third party to be able to access our information. So the argument is, if we're giving permission to a third party to access our location, how can we then argue that we have a reasonable expectation of privacy?" Steinhauser asked. 

The courts have not been fond of overly wide searches of busy areas like cities and stores. 

"I think that's always the concern," Steinhauser said. "How often and broad is it as far as ending up with a lot of innocent people, who had nothing to do with the event who end up basically with their cellphone information being given to the police." 

But more specific searches are viewed as less a potential problem. The night Alexa Bartell was killed, there were seven known rock throwing incidents. Investigators knew with great specifics not only the locations of the attacks, but in most cases times. 

Asking for that kind of specific data, gives the information a greater chance of surviving in court believes Steinhauser. 

"These types of broad geofencing warrants that are asking for large areas without being able to particularize where specifically they're looking. Those are the ones that are getting struck down," Steinhauser said. 

The contents of our phones such as pictures and text messages are a different matter and takes additional warrant applications. Those often follow when investigators find suspects.