LOS ANGELES (CBSLA) – The brutal assault on a 45-year-old father of four outside Dodger Stadium last week was precipitated by an altercation authorities announced Thursday, as detectives continue their search for his attacker.

Los Angeles police told reporters that in the early morning hours of March 29, Rafael Reyna got into a dispute with a young man and young woman as he was walking to his car in the parking lot of Dodger Stadium, near the end of the Dodgers extra-innings home opener against the Arizona Diamondbacks.

An undated photo of Rafael Reyna.

The dispute intensified, and the young man then punched Reyna.

“The dispute escalated, ultimately ending in when the young man struck Mr. Reyna with a single punch,” LAPD Capt. Billy Hayes said at a Thursday afternoon news conference. “Mr. Reyna fell to the ground, landing on his buttocks, fell backwards, and struck his head on the pavement, sustaining significant head trauma.”

Reyna was FaceTiming with his wife, Christel, when the attack happened. She told CBS2 Sunday that she could hear someone yelling at her husband, and then heard a loud thump. She remained on the phone as strangers tended to her husband.

Reyna remains in critical but stable condition Thursday at LAC+USC Medical Center.

The two men did not know each other prior to the attack, Hayes said, adding that he believes he knows what prompted the altercation, but would not disclose that detail.

Los Angeles police hold a news conference on April 4, 2019, to provide an update on the attack against Rafael Reyna. (CBS2)

“My belief and my rational for that is, I’d like to get independent accounts of what transpired there rather than tainting anybody that would come forward with what I believe my opinion and other witnesses’ opinions are,” Hayes explained.

Investigators have been combing over surveillance video to try and identify the man and woman.

The attacker was described by a witness as a Hispanic man in his mid-20s, about 5-foot-8 and weighing 150 pounds. He is clean shaven. He was last seen wearing a gray sweatshirt, blue jeans and a blue Dodgers baseball cap.

The woman he was with was described as Hispanic, in her 20s, 5-foot-4, weighing 110 pounds with long black hair and a thin build. She was wearing a white Dodgers jersey and blue-jean shorts.

Police had previously identified a white SUV as a possible suspect vehicle. However, investigators have since found the vehicle and spoken to the individuals associated with it, determining they were not involved in the attack.

“We cannot express enough that we believe there are additional witnesses to the incident, and that there are individuals who are aware of the identity of this young man and young woman,” Hayes said.