Police say Travis Reinking, 29, killed four people and wounded four others with an AR-15 rifle Sunday as he stormed the restaurant in Nashville wearing nothing but a green jacket.
But Reinking had exhibited erratic behavior for years before the shooting. Darlene Sustrich, who co-owns a Colorado crane company where Reinking once worked, said they got a call from the Secret Service after he refused to leave a restricted area at the White House last July.
"We told them, 'Hang onto him if you can. Help him if you can,'" Sustrich said.
Federal officials did not immediately respond to a request for comment.
Reinking has been charged with four counts of criminal homicide. And a tweet from the Metro Nashville Police Department said he also faces four counts of attempted murder and one count of unlawful possession in the commission of a violent felony.
Davidson County Sheriff Daron Hall said Tuesday that Reinking has been "compliant" and "cooperative" since he was transferred to the jail late Monday after he was captured near the apartment where he lived. Reinking is wearing a vest known informally as a "suicide smock" and will remain under close observation at a maximum-security facility in Nashville.
An attorney listed as Reinking's lawyer did not immediately respond to an email seeking comment.
Meanwhile, the man who snatched the rifle away from the gunman during the shooting told Tennessee lawmakers Tuesday he faced "the true test of a man," drawing a standing ovation during his brief address. As the state House hailed him as a hero, James Shaw Jr. said he acted to save his own life early Sunday and saved others in the process.
"I never thought I'd be in a room with all the eyes on me, but you know, I'm very grateful to be here," Shaw told House members. Shaw said he has gone to see some of the shooting victims in the hospital and they all remembered him. He apologized to the people whose loved ones died in the attack.
The state Senate also honored Shaw on Tuesday.
After the shooting, authorities say Reinking escaped on foot from the restaurant and shed his only item of clothing. By the time he was captured in the woods nearby, police had searched his apartment and found the key fob to a stolen BMW they had recovered in the parking lot days earlier. The BMW theft had not initially been tied to Reinking.
Police seized multiple items from his apartment including: a Remington rifle with a magazine, cartridges for different calibers of guns, two rifle scopes and gun cleaning equipment. Police also found three books on patents in the apartment, along with a sketchbook, two iPhones and a number of pieces of computer equipment, court records show.
Nashville Police Department Lt. Carlos Lara told reporters Reinking was arrested Monday after detectives were tipped to the suspect's presence by some construction workers. He carried a black backpack with a silver semi-automatic weapon and .45-caliber ammunition.
The arrest ended a 24-hour manhunt involving more than 160 law enforcement officers, but it left troubling unanswered questions about official responses to months of bizarre behavior before the restaurant attack, including encounters with police in Illinois and Colorado and an arrest at the White House that raised red flags.
Sustrich, Reinking's former boss, described him as appearing paranoid and delusional at times. A former co-worker told a Salida, Colorado, police detective Reinking was infatuated with singer Taylor Swift and claimed to be a sovereign citizen.
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. The suspect told Washington, D.C., police he was a sovereign citizen and had a right to inspect the grounds, according to an incident report.
Reinking was not armed at the time, but at the request of federal agents, Illinois police revoked his state firearms card. Four guns, including the AR-15 used in the shootings, were transferred to his father, a procedure allowed under Illinois law.
Tazewell County Sheriff Robert Huston said Jeffrey Reinking pledged he would "keep the weapons secure and out of the possession of Travis." Don Aaron, a Nashville Police spokesman, said Reinking's father "has now acknowledged giving them back" to his son.
Bureau of Alcohol, Tobacco, Firearms and Explosives special Agent Marcus Watson said Monday that his father's action is "potentially a violation of federal law."
Phone calls to a number listed for the father went unanswered.
Burke and Mattise reported from Nashville, Tennessee. Other contributors include John Raby in Charleston, West Virginia; Ed White in Detroit; Michael Kunzelman in Baton Rouge, Louisiana; Kathleen Foody in Denver, Colorado; and Justin Pritchard in Los Angeles.