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 OKLAHOMA CITY - Oklahoma Labor Commissioner Mark Costello was stabbed to death by his son, Christian Costello, at a metro Braum's, police say. 
 
 It happened around 6:30 Sunday night at the Braum's at 11224 North May. 
 
 Pam Pollard with the Oklahoma Federation of Republican Women said she spoke to Costello's family and his chief of staff and confirmed the news Sunday night. 
 
 Sources say Costello's son had reached out to his parents and asked them to meet him at the restaurant. 
 
 Police say it started inside the Braum's with the suspect stabbing the victim and then proceeded outside. 
 
 Patrick Spencer was driving on May when he saw someone he thought had been shot. 
 
 "We got a closer look and there was a guy chasing him with a knife," said Spencer. "It was shocking and dramatic." 
 
 Spencer says the men circled the building a couple of times. 
 
 He watched while he called 9-1-1. 
 
 "It was very cold you know the way he was walking after the victim. There was never any rush to the entire thing. There was another woman involved. We assume that's his wife of the victim. She was running after them. But it was a very brisk walk type run," said Spencer. "At one point, the suspect stabbed the victim in the head. We saw that in front of us." 
 
 Police say Christian Costello stabbed his father multiple times, causing his death. 
 
 "He was pretty bloody and the wife was trying to get him in their vehicle to get him away from the suspect," Spencer said. 
 
 Spencer says it ended when a witness in the parking lot rammed the suspect with his vehicle, knocking him to the ground. 
 
 Several people then tackled him and kicked the knife away. 
 
 "They tied him up with belts and they were able to keep him under wraps until police got there." said Spencer. 
 
 Oklahoma City Police Captain Paco Balderrama called the attack "gruesome" and "tragic." 
 
 Dozen of witnesses were interviewed by police Sunday night, both Braum's employees and customers. 
 
 Costello's son, Christian Costello, 26, was arrested for first-degree murder. 
 
 Governor Mary Fallin has announced that flags on state property will be lowered to half-staff through Friday to honor Mark Costello's life. 
 
 Flags on state property will be lowered to half-staff through Friday in honor of Mark Costello's life and service to the people of Oklahoma — Governor Mary Fallin (@GovMaryFallin) August 24, 2015 
 
 The Costello family released the following statement: 
 
 There are no words to express the shock and sadness that our family has experienced the last number of hours. The outpouring of emotion and support our family feels is tremendous. Our son, Christian Costello, has experienced many difficulties over the past several years. Christian, like thousands of Oklahomans, struggles with a mental health disease and like many families we did our best to support him. Mark was committed to being there for his son and provided whatever help he could as a father. We ask for your prayers and support as our family tries to cope with and understand this life-changing tragedy. Mark loved to brag about his kids and their successes, but like many in the public eye, he also viewed his family life as personal. We ask that you respect our family's privacy as we work through this very difficult time and please understand that our family will struggle with this for years to come as we try and find answers. 
 
 Report a typo ||||| OKLAHOMA CITY (AP) — Oklahoma's labor commissioner died after he was stabbed multiple times at an Oklahoma City restaurant, and his adult son has been arrested on a first-degree murder complaint in the slaying, police said. 
 
 Christian Costello, son of Oklahoma Labor Commissioner Mark Costello, is placed in a police car, Sunday, Aug. 23, 2015, at the scene where Mark Costello was fatally stabbed in Oklahoma City. Christian... (Associated Press) 
 
 Police investigate the scene where Oklahoma Labor Commissioner Mark Costello was fatally stabbed, Sunday, Aug. 23, 2015, in Oklahoma City. Christian Costello, son of Mark Costello, was arrested on a first-degree... (Associated Press) 
 
 FILE - In this Wednesday, Sept. 10, 2014, file photo, Oklahoma Labor Commissioner Mark Costello speaks during a news conference at the state fairgrounds in Oklahoma City. Authorities say Costello has... (Associated Press) 
 
 Police investigate the scene where Oklahoma Labor Commissioner Mark Costello was fatally stabbed, Sunday, Aug. 23, 2015, in Oklahoma City. Christian Costello, son of Mark Costello, was arrested on a first-degree... (Associated Press) 
 
 Oklahoma City police take photos of Christian Costello, son of Oklahoma Labor Commissioner Mark Costello, before placing him in a police vehicle, Sunday, Aug. 23, 2015, at the scene where Mark Costello... (Associated Press) 
 
 Officers were called around 6:30 p.m. Sunday to a Braum's ice cream and fast-food restaurant on the city's northwest side after a stabbing was reported, Oklahoma City Police Department Capt. Paco Balderrama said. Police found Labor Commissioner Mark Costello stabbed multiple times in the head and neck, Balderrama said. Costello, 59, was taken to a hospital, where he died. 
 
 State Medical Examiner's Office spokeswoman Amy Elliott said an autopsy would be performed. 
 
 Police said an altercation started inside the building and spilled into the parking lot, where bystanders helped subdue the attacker until officers arrived. 
 
 Costello's 26-year-old son, Christian Costello, was taken into custody in the parking lot and arrested on a first-degree murder complaint, Balderrama said. He remained in police custody late Sunday night. 
 
 Balderrama said he did not know whether the younger Costello had an attorney who could comment on the allegations. 
 
 Condolences poured in from state officials. 
 
 "Our hearts ache as an agency for this tragic event and our department grieves for his family during this very difficult time," Labor Department Chief of Staff Jim Marshall said in a statement. 
 
 Costello was married with five children. 
 
 "I'm just numb right now, as many of us are," Oklahoma Republican Party Chairman Randy Brogdon said. "He was a great Christian, a good man and a wonderful husband and dad. He is going to be sorely missed." 
 
 Republican U.S. Sen. James Lankford also lauded Costello, saying in a statement he was "passionate about our nation, conservative fiscal principles, and the people of our state." 
 
 "Mark was a friend, and as we grieve, we will also pray for his family as they deal with this unbelievable tragedy," Lankford said. 
 
 A successful businessman from Bartlesville who founded a telephone software company in 1984, Costello ousted the incumbent Democrat with 64 percent of the vote during a Republican sweep of statewide offices in 2010. He easily won re-election in 2014. 
 
 A strong proponent of smaller government, Costello closed the agency's Tulsa office, which he said was underused, and that the agency's technology upgrades had allowed much of its professional licensing services to be conducted online. 
 
 "You can reform government," Costello said during last year's campaign. "It can be done when there is political will. I have that political will," he said. 
 
 Costello also faced criticism for comments he made in 2011 in which he compared state bureaucrats to "feral hogs," a comment he later said was "an unfortunate animal analogy."
– Oklahoma's state labor commissioner was stabbed to death last night in a gruesome scene at an Oklahoma City restaurant, reports KFOR, and Mark Costello's own son is being held in his murder. Sources say Christian Costello, reportedly 26 or 27, asked his parents to meet him at the restaurant around 6:30pm after an argument that morning, and he then attacked his father with a knife. Mark Costello fled outside, with Christian following, witnesses say. “It was very cold ... the way he was walking after the victim," says a man who was driving by. "There was never any rush to the entire thing." The witness says that the elder Costello was stabbed in the head as his wife tried to get him in their car and away from the attack. Eventually, someone hit Christian Costello with their car, and other witnesses were able to subdue him until police arrived. Costello, 59, was transported to a local hospital with stab wounds to the head and neck, according to NBC News. He died last night. The politician was elected labor commissioner in 2010 and had four other children. Condolences continue to pour in for his family. "I'm just numb right now, as many of us are," Oklahoma Republican Party Chairman Randy Brogdon says, according to the AP. "He was a great Christian, a good man, and a wonderful husband and dad. He is going to be sorely missed." Christian Costello has been charged with first-degree murder.