Police have arrested one of the suspects in the Kansas City bar slaughter that left four dead and five injured — with a second still on the loose and deemed “armed and dangerous,” according to cops.

Javier Alatorre, 23, was busted late Sunday just across the state line in Kansas City, Missouri. He was charged with four counts of first-degree murder and held on $1 million bond, police said.

Hugo Villanueva-Morales, 29, was still being hunted as of early Monday — with Kansas police warning that he should be considered “armed and dangerous.” He was also charged with four counts of first-degree murder.

Alatorre’s arrest came shortly after police released a series of surveillance photos from the Tequila KC Bar and asked the public’s help in identifying the suspects.

They are accused of shooting up the private club around 1:30 a.m. Sunday, police said.

Bartender Jose Valdez told the Kansas City Star that one of the men had been thrown out earlier in the night after being refused a drink, coming back later and immediately shooting up the bar.

Police found four dead inside the bar — all Hispanic men — while five others who had been hit managed to flee. All are in stable condition, police said Sunday.