The shooting happened just after 4 a.m. Saturday when a group of four men got into a fight with another group including two men and two women near the elevators that lead to the garage for self parking.

According to the arrest report, the fight started when one man made comments about Shepherd's sister. Shepherd told him that type of talk was disrespectful, according to the report.

The man, identified in the arrest report as Terrance Aubry, 19, told Shepherd that his sister was a "bad bitch," implying she was attractive, the report said.

Fisticuffs ensued, and Shepherd was punched in the face, the report said. He then got on an elevator with his sister and went to the parking lot, where Shepherd's sister tried to talk him out of returning to the casino, the report said.

Shepherd is seen on surveillance video chambering a round into a gun in the elevator as he heads back to where the fight occurred, the report said. When he returned to the casino level, he started shooting when the elevator doors opened, the report said.

Shepherd fired at least four shots, striking 20-year-old Vance Davis and 23-year-old Markael Ballou, neither of whom were involved in the fistfight, the report said.

Both were treated and released from University Medical Center.

Shepherd was identified as the shooter by several witnesses who picked him out of photo lineups, according to the arrest report. The surveillance video of the incident was not released to the public.

Shepherd has a criminal record consisting of misdemeanor offenses including disturbing the peace and resisting a public officer, according to Las Vegas police records.

The police department's gang crimes bureau was involved in the investigation because initial reports indicated the shooting might have been gang-related. Police recovered two guns from the scene, including one that fell from the pants of one of the victims but was not fired, according to the arrest report.

Las Vegas police Capt. Al Salinas said Wednesday that officers determined that Shepherd was not a gang member and that the shooting was not gang-related.

Whether anyone else will be charged was unclear.

The incident was the second shooting at a Strip casino in less than a month. Four people were wounded by a gunman who fired onto the New York-New York casino floor from a balcony in the wee hours of July 6.

Four tourists tackled Steven Francis Zegrean, 51, before he could reload and continue shooting, police and witnesses said. Zegrean was arrested on multiple counts.