NASHVILLE, Tenn. (AP) - The mentally unstable gunman suspected of opening fire at a Waffle House restaurant in the middle of the night was arrested not far from his apartment Monday after hiding from police for more than a day following the attack that killed four people, authorities said.

Authorities had mounted a massive manhunt for 29-year-old Travis Reinking, after the Sunday morning attacks, in which a gunman clad only in a jacket used an AR-15 rifle to kill four and injure others.

Metropolitan Nashville Police announced Monday on Twitter that he was taken into custody not far from his apartment.

A detective from the department's specialized investigations division's narcotics unit spotted Reinking in a wood area near a construction site, Lt. Carlos Lara told news reporters.

He said construction workers told officers a person matching the suspect's description walked through the area and into woods. When confronted, the suspect lay down on the ground, and officers cuffed him, Lara said.

He said Reinking carried a black backpack that held a silver semi-automatic weapon and .45-caliber ammunition. Detectives cut the backpack off of the suspect, he said.

Police spokesman Don Aaron said Reinking requested a lawyer, was taken to a hospital and would later be booked on four counts of criminal homicide.

Reinking, described as a white man with brown hair, 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.

Police say about 20 people were in the Waffle House at the time of the shootings. They included people of different races and ethnicities, but the four people killed were minorities - three black and one Hispanic.

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.

Police said Reinking stole a BMW days before the attack. The car was quickly recovered, but authorities did not immediately link it to Reinking.

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 entered 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.

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, Aaron said. A federal official says the father could face charges for returning guns.

Bureau of Alcohol, Tobacco, Firearms and Explosives special Agent Marcus Watson said at a news conference Monday that Jeffrey Reinking's act of returning the guns to his son is "potentially a violation of federal law."

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 worked in construction for a while.

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.

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.

Akilah Dasilva was also killed inside the restaurant. The 23-year-old from Antioch was a rap artist and music video producer.

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."