Authorities are investigating after an inmate at the Dallas County Jail beat his cellmate to death just 10 minutes after being transferred to that cell.

Patrick Martin killed Javier Leal after an altercation that was largely unprovoked, according to an arrest warrant obtained by News 8.

Martin, 39, had gotten down from the top bunk to use the restroom “when he felt [Leal’s] body heat and flinched.”

“The suspect then turned around [and] without provocation struck the complainant in the face with a closed fist while he lay in the lower bunk,” the warrant reads.

Leal, 56, fell out of the bed and grabbed Martin around the waist before Martin allegedly struck him in the side of the head repeatedly with his fists and elbows.

Martin told investigators he hit Leal 30 times with his right elbow before Leal fell and hit his head on the toilet. He then continued to stomp Leal with his feet, according to the warrant.

Martin pushed the cell’s intercom requesting help after the attack.

The warrant states four officers responded to the incident in the jail's north tower around 2 a.m. Dec. 30. They found Martin and Leal covered in blood, and blood stains on the cell's floor and walls.

Leal was unconscious and unresponsive, and was taken to Parkland Hospital for treatment. A nurse there told an officer that Leal had “severe brain and head trauma and had to be on machines to sustain life.”

Leal was pronounced dead just after noon on Dec. 31.

The arrest warrant, obtained before Leal had died, said Martin would be charged with felony aggravated assault. It was unclear if that charge would be upgraded. A bulletin sent out after Leal’s death said only that criminal charges had been filed.

Jail records indicate Martin had previously faced multiple assault charges as well as a drug offense and fare evasion. Leal’s inmate record appeared to have been removed as of Wednesday afternoon.