SAN ANTONIO -

The Bexar County Sheriff's Office announced some major changes in their jail operations on Thursday after an investigation uncovered illegal activity within the jail.

Bexar County Sheriff Susan Pamerleau said the department has had a problem with cell phones getting into secure areas of the jail.

Recently, two inmates were caught with cell phones: Paul Reyes and Roland Ponce, 24.

According to an arrest affidavit, the phone was snuck in by Stephen Kpehe, 20, in early December.

Kpehe (pictured below) worked in the commissary at the jail and delivered the phone to Roland Ponce by hiding it in a box of sugar substitute.

The affidavit also states that Roy Ponce, 22, who is Roland's brother, had paid Kpehe to get it to him.

All four are charged with bringing prohibited items into a correctional facility.

However, some changes have been made, including adding an $8,000 screening system to the secure area of the jail and setting a standard that everyone -- employee or civilian -- will have to go through that scanner.

"There is now only one single entrance and exit for the secure part of the adult detention center main jail," said Deputy Chief Raul Banasco. "There had been a prior practice of several areas coming in. Everyone who enters the jail, whether they are a staff member, a visitor, or a volunteer, or a vendor will have to be fully screened."

Banasco said the new screening system is very advanced and detects illegal items, specifically cell phones.

"Whenever a cell phone is brought into the secure confines of a detention correctional environment , those phones can be used for illegal activities that can compromise the safety of the jail or maybe have some outside connection to criminal activity," said Banasco.

"This is for everyone," said Pamerleau. "Regardless, if there was a motive or whether or not it was innocent and inadvertent, this is to protect everyone."