Authorities had mounted a massive manhunt for 29-year-old Travis Reinking, after the Sunday morning attacks.
Authorities announced the arrest Monday afternoon on Twitter, but did not immediately give details.
BREAKING: Murder suspect Travis Reinking is in custody. Arrested moments ago. pic.twitter.com/WwuDCXDCGQ— Metro Nashville PD (@MNPDNashville) April 23, 2018
More than 100 Nashville police officers had been 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.
Police said he had stolen a BMW days before the attack. The car was quickly recovered, but authorities did not immediately link it to Reinking.
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.
RELATED: 'Hero' bystander James Shaw Jr. wrestled gun away from Waffle House shooter
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.
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.
RELATED: Waffle House shooting suspect arrested last year near White House
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.
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.
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.
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 entered 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."
Associated Press writers John Raby in Charleston, West Virginia; Ed White in Detroit; and Justin Pritchard in Los Angeles contributed to this report.
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