NASHVILLE, Tenn. (AP) — A mentally unstable gunman stole a BMW from a dealership and escaped capture days before killing four people at a Waffle House, police said Monday as their manhunt intensified more than 24 hours the attack.

“The crime he committed, a quadruple murder, there’s nothing more urgent than that, to find the person responsible,” Nashville Police spokesman Don Aaron said. “Given his exhibited mental instability over many months that we’re aware of, that’s certainly another layer of urgency.”

The car stolen Tuesday was recovered that day near the apartment of Travis Reinking, but police didn’t connect him to the theft until after the restaurant attack, when they found the car keys in his apartment, Nashville Police spokesman Don Aaron said.

Reinking, 29, was last seen hours after the attack Sunday morning, walking along some woods near that apartment, wearing nothing but a black pair of pants. He’ll have to come out sometime, Aaron told a news conference.

“If Reinking is still in the woods, he’s been there now for more than 24 hours, and at some point he’ll have to come out for more food and water,” Aaron said. He encouraged people in the immediate area of Nashville to remain vigilant, but also said the search area may be expanding soon.

“We don’t know where he is. He may have left the area,” Aaron said.

More than 100 Nashville police officers were going door-to-door and searching wooded areas, joined by dozens of agents with the FBI, the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives and troopers with the Tennessee Highway Patrol.

Reinking was wearing only a green jacket when he opened fire with an AR-15 in the Waffle House parking lot and then stormed the restaurant shortly after 3 a.m. Sunday, police say. Four people were killed and four others were injured before a quick-thinking customer wrestled the assault weapon away, preventing more bloodshed. Reinking then disappeared, police said.

It’s not clear why Reinking opened fire on restaurant patrons, though he may have “mental issues,” Metropolitan Nashville Police Chief Steve Anderson said earlier. He’s considered armed and dangerous, because he was known to have owned a handgun authorities have not recovered.

Aaron ruled out a report Monday of multiple gunshots fired in the search area, noting that a gun range is nearby.

Meanwhile, authorities in Illinois shared past reports suggesting multiple red flags about a disturbed young man with paranoid delusions.

In May 2016, Reinking told deputies from Tazewell County, Illinois, that music superstar Taylor Swift was stalking him and hacking his phone, and that his family was also involved, according to a report released Sunday.

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

Another sheriff’s report 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.

Last July, Reinking was arrested by the U.S. Secret Service after he crossed into a restricted area near the White House and refused to leave, saying he wanted to meet President Donald Trump. Reinking was not armed at the time, but at the FBI’s request, state police in Illinois revoked his state firearms card and seized four guns from him, authorities said.

The AR-15 used in the shootings was among the firearms seized.

Then, in August, Reinking told police he wanted to file a report about 20 to 30 people tapping into his computer and phone and people “barking like dogs” outside his residence, according to a report.

“There’s certainly evidence that there’s some sort of mental health issues involved,” Tazewell County Sheriff Robert Huston said. But he said deputies returned the guns to Reinking’s father on the promise that he would “keep the weapons secure and out of the possession of Travis.”

Reinking’s father “has now acknowledged giving them back” to his son, Nashville Police spokesman Don Aaron said.

Phone calls to a number listed for the father, Jeffrey Reinking, went unanswered.

It is not clear why Reinking moved recently from Morton, Illinois, and if it had anything to do with being near Swift, who has a home in Nashville. Police say he was employed in construction for a while, and there would have been enough work in the booming city for him.

Police say Reinking drove into the Waffle House parking lot in his gold Chevy Silverado pickup early Sunday and sat there for about four minutes before opening fire outside the restaurant.

The victims fatally shot in the parking have been identified as Taurean Sanderlin, 29, of Goodlettsville, and Joe Perez, 20, of Nashville.

Sanderlin was an employee at 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.”

Reinking then went inside the restaurant and opened fire, police said.

One of the fatally wounded inside was DeEbony Groves, a 21-year student at Nashville’s Belmont University. She was remembered as an exceptional student who made the Dean’s list, and a tenacious basketball player.

“She was a brilliant young lady, very, very intelligent and a very hard worker,” Gallatin High School basketball coach Kim Kendrick told The Tennessean.

Akilah Dasilva was also killed inside the restaurant. The 23-year-old from Antioch was a rap artist and music video producer who had such skills behind the camera that he was a favorite among many of Music City’s independent musicians and recording labels, The Tennessean reported.

“Music is my life and I will never stop until I achieve my dreams,” Dasilva said on his Twitter account.

Dasilva’s mother told CBS News that her son was a student at Middle Tennessee State University and aspired to be a music engineer.

He was at the restaurant with his girlfriend, 21-year-old Tia Waggoner, the paper reported. Waggoner was wounded and is being treated at Vanderbilt University Medical Center. Dasilva’s family said she underwent surgery and doctors were trying to save her leg.

Police say Sharita Henderson, 24, of Antioch, was wounded and is being treated at VUMC.

Also wounded was James Shaw Jr., a 29-year-old restaurant patron who burned his hand grabbing the hot muzzle of the assault weapon as he wrestled the gun away. A Nashville native who works as a wireless technician for AT&T, Shaw said he was no hero — despite being hailed as one by Nashville Mayor David Briley.

Shaw said he pounced on the suspect out of self-preservation, after making up his mind that “he was going to have to work to kill me.”

This photo provided by Metro Nashville Police Department shows Travis Reinking, who police are searching for in connection with a fatal shooting at a Waffle House restaurant in the Antioch neighborhood of Nashville early Sunday, April 22, 2018. (Metro Nashville Police Department via AP)