A gunman wearing nothing but a green jacket and brandishing an assault rifle stormed a Waffle House restaurant in Nashville and shot four people to death before dawn Sunday, according to police, who credited a customer with saving lives by wresting the assailant’s weapon away.The gunman opened fire at 3:23 a.m. (local time) on Sunday and before a "hero" patron, James Shaw, Jr., wrestled away the gunman's rifle, according to police.Police identified the suspect as Travis Reinking, 29, of Morton, Illinois. The pickup truck the gunman used to drive to the restaurant was registered to Reinking.The search for Reinking continued into the evening. "Search continuing for accused quadruple murderer Travis Reinking," the Nashville Police Department tweeted on Sunday. "More than 80 MNPD officers are joined this evening by our partners from the THP, FBI & ATF. See Reinking? Please call 615-862-8600 immediately. One of his guns, a pistol, remains unaccounted for."Nashville Police Department spokesman Don Aaron said three people died at the scene and one person died at Vanderbilt University Medical Center. Two other people were being treated there for gunshot wounds. Medical Center spokeswoman Jennifer Wetzel said one was in critical condition and the other was in critical but stable condition.Police released the names of some of the victims Sunday afternoon. One of the victims, 29-year-old Taurean Sanderlin, was a Waffle House employee. Two other victims, 20-year-old Joe Perez and 23-year-old Akilah Dasilva, were patrons of the restaurant. The identity of the fourth victim, a 21-year-old woman, is not being released until her family has been notified.Aaron said the gunman arrived at the restaurant, sat in the parking lot for four minutes and shot two people with an assault rifle. The gunman then went inside and continued firing. Police are urging nearby residents to lock their doors while officers search for the gunman, who fled the scene on foot.Reinking's state firearms card was revoked last year by state police, but his guns were given to his father with the promise that they wouldn't be shared with his son, police said.Police said the assailant shed his jacket and fled on foot. Police later issued warnings to the public and referred to the suspect as nude. By later Sunday morning, police said the suspect may have put on black pants."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."Nashville Mayor David Briley said the shooting represents “a tragic day” for the city.“My heart goes out to the families & friends of every person who was killed or wounded in this morning’s shooting. I know all of their lives will be forever changed by this devastating crime,” Briley said on Twitter.So far, the motive for the shooting appears to be random, police said.Secret Service Agent Todd Hudson in Nashville says Reinking "wanted to set up a meeting with the president" last July when he was arrested outside of the White House. Hudson says Reinking tried to cross bike racks near the White House grounds that were part of security barriers. He was asked to leave the restricted area, and when he declined, Hudson says he was arrested on a charge of unlawful entry.The Associated Press contributed to this report.