A 21-year-old airman opened fire at a Walmart in North Dakota, killing one employee early on Tuesday.

Officials say that Marcell Willis shot and wounded a second Walmart employee before he shot himself with a handgun. He also fired once at a third employee but missed, authorities said.

The shooting began after Willis walked into the supercenter in Grand Forks around 1 a.m. on Tuesday. He then apparently opened fire.

Grand Forks Police says the suspect was active duty Air Force and stationed at the Grand Forks Air Force base, reports CNN affiliate WDAY. He later died at a hospital.

A witness named Andy Legg says he was shopping in the store when he heard three or four gunshots a little after 1 a.m. He then heard people running and screaming.

"Just replaying it in my head it's still kind of hard to grasp," Legg said.

According to police, Willis had no obvious connection to the victims.

"We are deeply saddened about this situation and our thoughts and prayers are with the victims and their families," Walmart spokesman Brian Nick said. "We are still learning information about the events surrounding this tragedy and assisting law enforcement in their investigation."

Following the deadly shooting, Mayor Michael Brown said the tragedy has rocked the entire town, which consists of 55,000 residents.

"I can't remember anything this tragic in our community and that's why I think it's so shocking to happen like this," he said.

Eddy Eley of Grand Forks agreed.

"This happens in cities, big cities, not here and to know a couple people are gone because of it is devastating," Eley told ABC affiliate WDAZ. "I don't want to ever see that happen here again."

Military officials confirmed that the Air Force Office of Special Investigations is cooperating with police on the case.