Jesus I. Vargas, 30, of Mundelein, (inset) was charged in connection with a fatal stabbing in the 2000 block of Apache Trail in Round Lake Beach on February 28, 2022. | Background Photo: Joe Shuman/J. Shuman Photography (2022)

A Mundelein man being held on murder charges for allegedly stabbing a man to death in Round Lake Beach is facing new charges after he allegedly attacked a fellow inmate at the Lake County Jail.

Jesus I. Vargas, 30, of Mundelein, was charged with battery following the incident on May 24.

Lake County Sheriff’s Office Deputy Chief Christopher Covelli said Vargas was walking down the stairs from the second level of his jail pod area.

He approached a 34-year-old inmate, who is also assigned to the same pod.

Vargas clenched his fist and became aggressive with the other inmate, Covelli said.

The other inmate backed away from Vargas but Vargas punched him in the face.

Covelli said the other inmate defended himself and the correctional officer assigned to the pod ordered the two to stop.

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They continued fighting until officers sprayed them with pepper spray.

Vargas was determined to be the primary aggressor and the other inmate was not charged, Covelli said.

Vargas has been held in the Lake County Jail since March 2022 when he was charged with three counts of first-degree murder.

Police investigate a fatal stabbing in the 2000 block of Apache Trail in Round Lake Beach on February 28, 2022. | Photo: Joe Shuman/J. Shuman Photography (2022)

The fatal stabbing occurred around 3 p.m. on February 28, 2022, in the 2000 block of Apache Trail.

Officers arrived and found Vargas suffering from multiple lacerations, according to Lake County Major Crime Task Force Spokeswoman Heather Cognac.

Officers also found a man, identified as Brian Mahdee, 37, of Round Lake Beach, deceased in the garage of the residence.

A witness at the scene reported that Mahdee was unarmed and was stabbed by Vargas multiple times, Cognac said.

After stabbing the victim, Vargas cut himself multiple times, the witness told police.

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Vargas was transported to Advocate Condell Medical Center in Libertyville with non-life-threatening injuries.

After being released from the hospital, Vargas was interviewed by investigators and admitted to stabbing Mahdee following a verbal altercation.

Vargas and Mahdee were believed to be in a romantic relationship, Cognac said.

An autopsy showed that Mahdee was stabbed over 10 times.

Vargas remains held in the jail on a $3 million bond. He appeared in court Thursday on the new charge.