CALDWELL COUNTY, Texas (KXAN) — It’s been one year since the disappearance of Jason Landry, a 21-year-old Texas State University student who was heading home for the holidays when his car was found crashed on a rural road near Luling.

In the year since, family members, loved ones and investigators still seek answers to what factors may have led up to Landry’s disappearance — and cell phone data lies at the root of a professional disagreement between investigators working on the case.

A petition circulating online advocates for the use of a geofence warrant in Landry’s missing persons case. Geofencing, or geographical fencing, is a data tool that can be employed by law enforcement to help narrow in on potential witnesses in the vicinity of a crime by tapping into cellular data found in a set area around a crime scene.

Geofencing, however, requires a warrant in order to authorize its use, said Jeff Ferry, a captain specializing in criminal investigations at the Caldwell County Sheriff’s Office. The request for a warrant requires evidence related to the probable cause that a crime occurred.

At issue: Under Caldwell County officials’ current investigation, Ferry said the department has not received substantial evidence to suggest foul play occurred. But some other investigators looking into the case said they have received tips and interviewed subjects that might dispute that.

Abel Peña serves as managing director of the nonprofit organization Project Absentis, a group that assists law enforcement agencies on missing persons cases. He is doing work for the family pro bono.

Peña said he respectfully disagreed with law enforcement’s assessment of the lack of others with Landry at the time of his disappearance. He said the use of geofencing, and accessing potential cell towers and their data in the surrounding area, could provide further answers on what happened one year ago.

But he did note the privacy concerns affiliated with the practice. Under the Fourth Amendment, citizens are protected from unlawful searches and seizures of their private property, information or other materials.

However, he cited “possible circumstantial evidence” that could narrow into possible leads on the case.

“The information that we have, the evidence that we’ve collected, the interviews we’ve conducted — when you couple all that together and put that on a search warrant, you do have possible circumstantial evidence, which can lead to at least those first steps in looking at the case not as a missing persons case, but as maybe something that could have happened to Jason,” he said.

Peña said law enforcement have conducted six searches of the area where Landry’s car was found, and neither human remains nor further evidence has been uncovered that could paint a clearer picture on potential causes that led to his disappearance.

One year out from Landry’s initial disappearance, Peña said he and his investigators will continue to interview sources and bring that information to Caldwell County, the Texas Rangers and other law enforcement agencies, all while continuing to advocate for this geofencing warrant.

Professional disagreements happen in these cases, Peña said, noting his own experience as an FBI agent and differing opinions on case leads. But for now, he said their focus is to continue working with all interested parties to move the need closer toward accessing a warrant.

Ferry said that, as of now, the department has not received any evidence suggesting to the presence of another person with Landry at the time of his disappearance, or the potential of any crime having been committed against him.

With privacy concerns surrounding data access and potential affiliations of people in the vicinity with this crime, he said the only signature necessary to grant a geofencing warrant isn’t from a petition, but a judge signing off on its clearance.

For Ferry, he said this has been one of the most frustrating cases he and his team have worked on.

“We have been putting a lot of resources into it. We have been putting our time and man-hours into this. And we’ve met with people around the country, really, that have been invested in getting answers and getting the truth,” he said. “I am confident that in time, we’ll have that answer. It won’t be a timeline that any of us like, but I am absolutely confident that we will get answers.”

Anyone with information on Landry’s missing persons case can contact Ferry’s office at (512) 398-6777, ext. 4504, or via email at jeff.ferry@co.caldwell.tx.us. Those with information on his disappearance can also contact Project Absentis’s anonymous tip line at (726) 777-1359 or via email at projectabsentistips@protonmail.com.