The gunman who opened fire at a Nashville Waffle House with an AR-15 wearing nothing but a green jacket is still on the run and police have warned he is armed and dangerous.

Travis Reinking, 29, shot dead four people and injured several more at the Waffle House in Antioch early Sunday morning before shedding his jacket and fleeing.

More than 80 Nashville police officers continued to search for Reinking early Monday as disturbing reports about the wanted man's past behavior came to light.

Nashville Police Chief Steve Anderson said there was no clear motive for the shooting but noted that Reinking may have 'mental issues.'

Police said Reinking had his Illinois gun license revoked last year at the request of the FBI and four of his weapons were seized by authorities in Tazewell back in October.

Travis Reinking, 29, shot dead four people and injured seven others at the Waffle House in Antioch early Sunday morning before shedding his jacket and fleeing

The guns, however, were eventually returned to Reinking's father who has since admitted to giving them back to his son. The AR-15 used in the Waffle House shooting was among the four weapons.

Police recovered three of the four guns that were originally taken from Reinking, but believe he is armed with at least one handgun.

Authorities seized Reinking's weapons following an incident at the White House in July last year when he was arrested by the Secret Service for crossing an exterior security barrier and charged with unlawful entry.

Reinking told Secret Service officials he was trying to set up a meeting with President Donald Trump.

According to Heavy, a poster on Reddit said before Reinking's arrest at the White House that he had wanted to 'kill Trump'. The poster referred to Reinking as 'schizophrenic' and 'unstable.'

However the arrest report at the time did not indicate that Reinking wanted to kill the President.

Prior to the White House incident, police reports have previously described Reinking as 'delusional' and talked about his 'mental health issues'.

In May 2016, deputies from Tazewell County, Illinois, were called to a CVS parking lot where Reinking told officers that Taylor Swift was stalking him and hacking his phone, and that his family was also involved, according to a report released Sunday.

It is not clear why Reinking moved to Nashville and if it had anything to do with being near the pop/country superstar.

In August, after the White House incident, Reinking told police in Tazewell County, Illinois, that he wanted to file a report about 20 to 30 people tapping into his computer and phone. He also complained that people were 'barking like dogs' outside his residence, according to a report.

Reinking agreed to go to a local hospital for an evaluation after repeatedly resisting the request, the report said.

Another report from the sheriff's office said Reinking barged into a community pool in Tremont, Illinois, last June and jumped into the water wearing a pink woman's coat over his underwear. Investigators believed he had an AR-15 rifle in his car trunk, but it was never displayed. No charges were filed.

The AR-15 (above) used in the Waffle House shooting was among Reinking's four weapons that the FBI confiscated in October following an incident at the White House

Police said arrest warrants charging Reinking with murder have been issued as authorities continue to search for the gunman following the Waffle House shooting

Restaurant worker Taurean C. Sanderlin, 29, and 20-year-old customer Joe R. Perez were among the four shot dead by a gunman at a Nashville Waffle House on Sunday

Deebony Groves, 21, and Akilah Dasilva, 23, were also killed when the gunman stormed in and opened fire with an assault rifle

The Metro Nashville Police Department said arrest warrants charging Reinking with murder have been issued as authorities continue to search for the gunman.

'He's on foot,' Nashville Police Chief Steve Anderson said. 'Unless he's been picked up by a car, he would be fairly close. We don't want to alarm people, but certainly, everybody should take precautions. It could be he's in an unoccupied house. We want everybody to be concerned. Neighbors should check on each other.'

Officials with the Nashville public school system say schools will go into 'lock-out' mode if Reinking isn't found in time for class Monday.

Police said he arrived at the Waffle House before dawn on Sunday and waited in the parking lot for four minutes before shooting two people outside.

When Reinking entered the restaurant, a hero diner identified as James Shaw Jr managed to grab the rifle and toss it over a counter.

The gunman then fled and was seen walking, nude, on a road, authorities said.

Witnesses said he ran to a nearby apartment complex where he lived and put on black pants before entering the woods barefoot.

Hero diner James Shaw Jr managed to grab the rifle and toss it over a counter after the gunman opened fire. Shaw shows off his injured hand after he grabbed the gun barrel

A SWAT team swarmed his apartment in the morning with their guns drawn and screamed at nearby residents to 'get back'.

Police declared the scene clear at about 3pm, with no sight of Reinking.

Authorities used helicopters and dogs to search a wooded area near Reinking's apartment.

Authorities identified those killed in the shooting as 29-year-old restaurant worker Taurean C. Sanderlin of Goodlettsville, 20-year-old restaurant patron Joe R. Perez of Nashville, 23-year-old Akilah Dasilva of Nashville and Deebony Groves, a 21-year-old woman from Gallatin, Tennessee.

Sanderlin and Perez were killed outside the restaurant and Dasilva was critically wounded inside and later died at Vanderbilt University Medical Center.

Groves was shot dead inside the restaurant.

Perez's mother posted a picture of her son on Facebook and asked for prayers, saying it was the hardest day of her life. 'Me, my husband and sons are broken right now with this loss,' Trisha Perez said in the post. 'Our lives are shattered.'

Groves, who was a student at Nashville's Belmont University, was remembered as an exceptional student who made the Dean's list and a tenacious basketball player.

Authorities seized Reinking's (above) weapons following an incident at the White House in July last year when he was arrested by the Secret Service for crossing a security barrier

Police said he arrived at the Waffle House before dawn on Sunday and waited in the parking lot for four minutes before opening fire

Coroners carry out a body from the Waffle House where four died in the early hours of Sunday

Three of the victims died at the scene and a fourth died at the hospital. Coroners could be seen removing bodies from the restaurant on Sunday afternoon

Two people - Shanita Waggoner, 21, and Sharita Henderson, 24, are also being treated for gunshot wounds at Vanderbilt.

James Shaw Jr., the man who wrestled the gun from the shooter, said he had only entered the restaurant just two minutes ahead of Reinking.

He said he had gone there to eat early on Sunday after visiting a nightclub.

When he heard the gunshots, Shaw said he initially thought they were stacks of plates that had fallen over. Shaw said it was then that he saw restaurant workers scatter and a body near the front door as the gunman burst through the entrance.

'He shot through that door; I'm pretty sure he grazed my arm. At that time I made up my mind... that he was going to have to work to kill me,' he said.

'When the gun jammed or whatever happened, I hit him with the swivel door.'

The gun then jammed up and Shaw said he managed to get one hand on the gun and grab it. He then threw it over the countertop and took the shooter with him out the entrance.

Shaw said the shooter then ran away.

Authorities are hailing Shaw a hero for preventing further bloodshed at the restaurant.

Police added Reinking to the Tennessee Bureau of Investigation's Top 10 Most Wanted List described him as being 6ft 4in and 180 pounds.

A SWAT team swarmed the gunman's apartment (above) in the morning with their guns drawn