PARK SLOPE, Brooklyn (WABC) -- An apparent argument over not saying "thank you" for opening the door of a Brooklyn smoke shop ended with a 37-year-old man fatally stabbed late Tuesday.

It happened around 10:20 p.m. at Park Slope Convenience on 4th Avenue in Park Slope.

"It was just about not saying 'thank you' for opening the door for him," employee Kharef Alsaidi said as he reopened the bodega.

Alsaidi said the victim opened the door for the suspect and then asked, "Why don't you say, 'Thank you for opening the door'?"

The suspect responded, "I didn't tell you to open the door for me."

The verbal dispute quickly escalated to a physical altercation that spilled outside the store, and the victim is said to have taunted the suspect, telling him, "Stab me if you can do it."

The suspect grabbed a knife from his bicycle and stabbed the victim the abdomen and neck, according to authorities.

"The victim started screaming, 'He stabbed me, he stabbed me,'" Alsaidi said.

He said the victim stumbled back into the store, "bleeding all over the floor."

The man was rushed to New York Presbyterian Brooklyn Methodist Hospital, where he was pronounced dead.

The suspect biked away south on the 4th Avenue.

No arrests have been made, and the investigation in ongoing.

"I tried to deescalate the problem by telling the guy, 'Just put the knife away. He's not worth it. It's not worth it," Alsaidi said. "I did my best to deescalate, but nothing worked."

Anyone with information is urged to call the NYPD's Crime Stoppers Hotline at 1-800-577-TIPS (8477) or for Spanish, 1-888-57-PISTA (74782). You can also submit tips by visiting the CrimeStoppers website at crimestoppers.nypdonline.org or by messaging on Twitter @NYPDTips.