The Chicago Park District demanded Wednesday that a clout-heavy security company explain how someone managed to smuggle a knife — subsequently used to stab a man and a woman — into a punk concert at Northerly Island.

The latest in a series of violent summer crimes at popular tourist venues started when 34-year-old Thomas Christensen got into an argument with a 29-year-old man and 34-year-old woman about 9:30 p.m. Tuesday at a bar inside Huntington Bank Pavilion at Northerly Island.

The three were there for a concert by the Dropkick Murphys and Rancid.

Thomas Christensen | Chicago Police

The argument spilled into the venue, where Christensen pulled a knife and stabbed the other man in the neck and face, police said. The woman suffered a cut to her abdomen. They were taken to Northwestern Memorial Hospital, where they were listed in serious and good conditions, respectively.

Christensen, who lives in the Humboldt Park neighborhood, faces one felony count of aggravated battery with the use of a deadly weapon and one misdemeanor count of battery, police said. A knife was recovered.

On Wednesday, Chicago Park District General Counsel Tim King was demanding answers from Monterrey Security, the firm hired by Live Nation to handle security at Northerly Island.

King questioned how anyone could manage to sneak a knife into a concert at Northerly Island when Monterrey Security guards are supposed to use metal-detector wands to screen concert-goers before they enter the popular venue.

“We have to find out what the heck happened,” King said.

King said LiveNation and its security sub-contractor, Monterrey, are working under terms of a ten-year deal “re-upped” four years ago.

The contract requires the venue manager to maintain “adequate security,” including using those detector wands to check all concert-goers for guns, knives or other weapons, King said.

“We keep it vague because tomorrow, industry standards may require bomb-sniffing dogs or a device to detect bomb-making residue on a person’s fingers. It all depends on what’s going on in the world,” King said.

Live Nation issued an emailed statement calling the safety of its “artists, fans and employees” the company’s “highest priority.”

“We are reviewing our search procedures and working with the Chicago Police Department to better understand the circumstances surrounding the incident and to ensure that we are following the most appropriate security practices…,” the statement said.

Juan Gaytan, the former Chicago Police officer who owns Monterrey Security, refused comment on the stabbing, but said the firm is “constantly refining our security programs.”

“I feel confident in our ability to provide a safe environment,” he said.

The firm was once co-owned by former Chicago firefighter Santiago Solis, brother of Ald. Danny Solis (25th), powerful chairman of the City Council’s Zoning Committee.

Bob O’Neill, president of the Grant Park Conservancy, said there was “no excuse” for the security lapse.

“Everybody is supposed to be subject to metal detector wands and after what happened at the Boston Marathon we have to be even more diligent,” O’Neill wrote in email.

O’Neill noted that security at Lollapalooza was vastly improved with an arrest rate of .00007%. “An event with 400,000 people can be safe, so there is no reason that Monterrey can’t do a better job at Northerly Island,” he said.

Monterrey has been at the center of controversy for years because of its parade of government contracts, including Soldier Field security.

In 2001, the company was slapped with a $22,000 fine by state regulators — and placed on two years’ probation — for operating for 21 months without a state license.

Current and former employees also accused the company of underpaying its workers on city jobs.

One year later, the Daley administration abruptly canceled Monterrey’s $2.9 million contract to secure city salt piles and equipment after admitting the deal violated the ethics ordinance that prohibits city employees from doing business with the city. Gaytan and Santiago Solis subsequently quit their city jobs.

In 2009, Monterrey traveled with then-Mayor Richard M. Daley, his Olympic bid team and VIPs to Denmark to make what turned out to be an ill-fated final pitch to the International Olympic Committee to choose Chicago as host of the 2016 Summer Olympic Games.

At the time, Monterrey was under fire for problems in emptying out the overflow crowd at a U2 concert at Soldier Field that occurred the week before the Copenhagen trip.

Monterrey volunteered to provide security for Chicago’s Olympic delegation in hopes of getting a piece of the Olympics pie. Instead, Rio de Janeiro was chosen to host the games.

Monterrey didn’t come away empty-handed. The firm had already won a contract from the Chicago 2016 organizing committee to handle security when the IOC evaluation team made its final visit to Chicago, securing and monitoring access to the hotel where the evaluation team stayed and met with Chicago’s bid team.