Cameron County Sheriff Manuel Trevino held a press conference on Thursday to provide details on the arrest of a former jailer at the Old County Jail.

Trevino said Lt. Alexander Lazo allegedly admitted to hitting three inmates in the back of the head with a metal pepper spray canister.

Lazo was arrested on Wednesday and arraigned Thursday. He was charged with three counts of aggravated assault by a public servant and issued a $90,000 bond, according to Trevino. Lazo served as a county employee for 14 years.

"As a department head, it's hard to arrest one of your own. But I made it real clear when I took office, that we were going to be transparent," Trevino said.

According to Trevino, the assault occurred on May 22 at the Old County Jail, where eight inmates started a fire inside a cell. As the inmates were being extracted, Lazo then allegedly assaulted three of the inmates.

The three inmates were taken to a local hospital to be treated for small injuries on the back of their heads, according to Trevino. There were back in custody that same day.

"One of the things I want to make absolutely clear, that while anyone is incarcerated in our facility, their rights will not be violated," Trevino said. "Additionally, I want to emphasize, that Lazo does not represent the hardworking women and men who serve with dedication and integrity at our detention centers every day. What he did is not what we practice here on a daily basis."

Trevino said the inmates who started the fire at the jail will be charged with arson and damaging county property. The fire remains under investigation.