By Holly Yan and Artemis Moshtaghian, CNN

(CNN) -- Nashville police are asking residents to lock their doors and stay alert after a seminude gunman killed four people at an area Waffle House early Sunday.

Police are also asking for the public's help in finding suspect 29-year-old Travis Reinking of Morton, Illinois. Authorities said the gunman arrived in a vehicle registered to Reinking, though he walked away from the restaurant, naked.

"Keep your doors locked, keep your eyes open. If you see this individual -- if you see a nude guy walking around this morning -- call the police department immediately," Metro Nashville police spokesman Don Aaron said.

The melee started around 3:23 a.m. (4:23 a.m. ET) in Antioch, southeast of Nashville.

After sitting in the truck for a few minutes, the gunman came out wielding an "assault-type rifle" and fatally shot two people outside the Waffle House, police said.

"He then went inside the restaurant (and) continued firing," Aaron said.

Some witnesses suffered cuts on their faces from shattered windows. Two more victims inside the restaurant were fatally shot.

Chuck Cordero, who was on break from his job as a 24/7 roadside serviceman, was about to walk in to the restaurant when the shooting took place.

"I was very lucky -- where I usually sit, one woman was killed and another was shot," he told CNN. "I was very fortunate to have not gone into the Waffle House and sat in my car."

Cordero added: "My friend 'T,' the cook at Waffle House, died trying to get away."

The carnage stopped only because of the heroics of a customer who heard the gunshots and hid near the restaurant's bathrooms.

Police said the customer, identified by a relative as James Shaw Jr., monitored the gunman's moves from afar and jumped into action when he saw an opportunity.

"He saw the gunman looking at his rifle. At that point, the shots had stopped. So he decided to rush the gunman, actually wrestled that assault rifle away, tossed it over the counter. At that point, the gunman then fled," Aaron said.

"He is the hero here, and no doubt he saved many lives by wrestling the gun away and then tossing it over the counter, and prompting the man to leave," he added.

Police said the assailant shed his jacket and fled on foot. Later Sunday morning, he apparently "clothed himself with a pair of pants," Aaron said.

"A man believed to be Travis Reinking was last seen in a wood line near Discovery at Mountain View Apts. on Mountain Springs Drive near the Waffle House," police tweeted. "The man was seen wearing black pants and no shirt."

Authorities have started drafting murder warrants against Reinking. But so far, the motive for the shooting remains unclear.

Waffle House, which has more than 1,500 locations across the country, offered its condolences.

"This is a very sad day for the Waffle House family," the restaurant chain tweeted. "We ask for everyone to keep the victims and their families in their thoughts and prayers."

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