The suspect has been identified as 29-year-old Travis Reinking of Morton, Illinois. Authorities said Reinking was nearly naked, wearing only a green jacket and carrying an assault-style rifle when he opened fire in the parking lot and then stormed the restaurant of Waffle House in Antioch, outside of Nashville, killing four people Sunday morning.
A federal official says Reinking's father could face charges for returning guns that were taken from him after an incident last year at the White House.
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."
Travis Reinking is accused of shooting four people to death early Sunday morning in Nashville. He was captured by authorities Monday afternoon.
Reinking's right to own guns was revoked by Illinois authorities after he was charged with "unlawful entry" at the White House last July. He was demanding a meeting with President Donald Trump.
Illinois authorities returned the guns to Reinking's father, who lives in Illinois. Authorities say the younger Reinking moved to Nashville last fall.
BREAKING: Travis Reinking apprehended moments ago in a wooded area near Old Hickory Blvd & Hobson Pk. pic.twitter.com/00ukga37s6— Metro Nashville PD (@MNPDNashville) April 23, 2018
"Once he got inside, it sounded like he just sprayed the rest of his bullets out," said witness Charles Cordero.
A 29-year-old male patron wrestled away the gunman's rifle, police said, and suffered minor injuries. The patron, James Shaw Jr. ran to the restaurant's restroom area and watched the shooting. When he saw Reinking looking at his rifle, he rushed him. He got the gun away from Reinking and threw it over the counter.
RELATED: 'Hero' bystander James Shaw Jr. wrestled gun away from Waffle House shooter
"I'm not a hero. I'm just a regular person," Shaw said.
After the shooting, Reinking shed his jacket and was nude when he went to a nearby apartment complex, where police believe he lives. A witness told police that they saw him leaving wearing only black pants, and he is believed to be shirtless and barefoot.
Monday morning, police said the suspect stole a BMW from a dealership and escaped capture days before the Waffle House shooting.
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.
There is still no clear motive, but police said Reinking may have "mental issues." Police reports from Morton describe a disturbed Reinking with paranoid delusions, and someone who liked firearms.
In May of 2016, deputies from Tazewell County, Illinois, were called to a CVS parking lot. Reinking told officers that singer Taylor Swift was stalking him and hacking his phone.
RELATED: Man wanted in deadly Waffle House shooting in Tennessee had delusions about Taylor Swift
Reinking told officers that Swift had told him to meet her at a Morton Dairy Queen and had hacked his phone and Netflix account. Reinking also believed that his family and police were involved in the harassment, officials said.
Reinking was arrested by agents with the U.S. Secret Service back in July after he crossed a restricted area near the White House. During that investigation, police confiscated those weapons, including the AR-15 he allegedly used at the Waffle House.
Investigators said Reinking's father got those guns back, and gave them back to his son.
Authorities identified the victims as Waffle House employee Taurean C. Sanderlin, 29, Joe R. Perez, 20, Akilah Dasilva, 23, and DeEbony Groves, 21. Sanderlin was an employee at the Waffle House.
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."
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.
RELATED: Gunman on the run after killing 4 at Waffle House
"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.
Officials with the Nashville public school system say schools will go into "lock-out" mode if Reinking isn't found.
During the lock-out, students will be free to move about the building but no guests or visitors will be allowed to enter the building.
The Associated Press contributed to this report