Kansas City, Kansas (CNN) Police in Kansas City, Kansas, have launched a manhunt for two men in connection with a bar shooting that left four people dead and five wounded.

The two men walked into the Tequila KC bar around 1:30 a.m. Sunday (2:20 a.m. ET) with handguns and started shooting, police said.

Police haven't named the suspects, but released security camera images of them.

Police spokesman Thomas Tomasic said witnesses told investigators that the shooting may have stemmed from an argument that occurred inside the bar hours earlier.

A bartender, Jose Valdez, told CNN affiliate WDAF the problem started when he refused to serve a man who'd caused problems months earlier. The man threw a glass at him and was thrown of the club, Valdez said.

A few hours later, that man and a second man came through the back door with pistols, he said.

"When he came in the second time he did not say nothing," Valdez said. "He just walked in and looked for who he was looking for and started shooting."

With about 40 people inside, the gunfire prompted customers to stampede out of the private, members-only venue, Valdez and Tomasic said.

The four slain men, all Hispanic males, were identified as a man in his late 50s, another in his mid-30s and two in their mid-20s, Tomasic said.

One of the men who died had planned to get married next year, said Shay Celedon, a bar patron who left two hours before the shooting.

"None of it really seems real right now. We were sitting here yesterday evening having drinks with my best friend's fiancé," Celedon said. "I go home, go to bed, get woken up two hours later that he's deceased, and she held him till he took his last breath, and tried to bring him back and keep pressure on his gunshot wound. And it was just one fatal shot that took him from us."

Another five people who had been shot were taken to area hospitals and were stable Sunday morning. At least two people have been released from the hospital, police said.

Investigators believe this is an isolated incident and "do not feel it's racially motivated," Tomasic said.

"We don't feel that these suspects are going to go out and do this again," he said.

Bar was a welcoming place

Friends of the shooting victims gathered outside the bar on Sunday

Celedon said she saw a man enter the bar in an agitated state. She said she saw him get into an argument with the bartender, at which point he was escorted out. She also saw him get into an argument with another individual before he left, she said.

Celedon said she left, but friends told her the man returned with a second person, resulting in a confrontation and shooting, she said.

Toni Maciel said the Tequila KC bar has a reputation as a gathering place for the community, and it was always a safe and welcoming place to adults from their 20s to their 60s. People would come after work for a drink, and guests generally know each other and their families.

Maciel said her cousins were among the wounded. She called on the suspects to turn themselves into police.

"Make it easier for yourselves. Find it in your hearts to do this, please. We have brothers, sons, cousins, uncles, that are no longer here because of your senseless act," she said.

Kansas Gov. Laura Kelly says the state is mourning the victims of "yet another mass shooting."

In a statement released by her office Sunday, Kelly said, "I continue to be frustrated that these mass shootings and killings occur with regular frequency. Our nation has an obligation to address this ongoing public health crisis."