Cesar Arturo Chaparro, 42, of Covington, Washington is held in King County Jail on suspicion of four counts of first-degree attempted murder and three counts of domestic violence. His bail is set at $1 million, reported The Seattle Times.
The deadline to file felony charges is Wednesday, prosecutors told The Seattle Times.
On Sunday at 1:30 a.m. at Muckleshoot Casino in Auburn, Washington, after watching his ex-wife dance with a man on the Club Galaxy dance floor, Chaparro allegedly fired his .40-caliber Glock handgun into the crowd.
Seven people were injured, including his ex-wife, her boyfriend and two of his ex-wife's sisters, although it was not clear who had been hit by gunfire or who was injured trying to escape the nightclub.
He was tackled by casino security immediately after the shootings, and the handgun was wrestled away from him.
Chaparro told Auburn police he followed his ex-wife (formerly identified by police as his estranged wife) and her boyfriend to the casino that night because he "could not stand it," reported The Seattle Times.
The four seriously injured victims were sent to Harborview Medical Center in Seattle. Two women remained in serious condition Monday and another was in satisfactory condition, hospital spokeswoman Susan Gregg told The Seattle Times. The man wounded from the shooting has been discharged from the hospital, Gregg said. Three others sent to Valley Medical Center in Renton were discharged Sunday.