Five people have been killed at yet another mass shooting, this time at a medical center in Tulsa, Oklahoma, after a man opened fire on a surgeon who he blamed for chronic pain after a recent back surgery.

Police say the man purchased an AR-style rifle just hours before what would be the 233rd mass shooting of the year, according to data from the Gun Violence Archive.

According to Tulsa Police Chief Wendell Franklin, the patient had called the clinic at the Saint Francis Health System repeatedly over complaints of back pain before targeting the surgeon.

The surgeon, Dr. Preston Phillips, was killed along with Dr. Stephanie Husen, receptionist Amanda Glenn and visitor William Love.

The shooter, identified as 45-year-old Michael Louis of Muskogee, killed himself in the attack.

In the aftermath of the shooting, Tulsa police Captain Richard Meulenberg called it a “catastrophic scene” with multiple injured and several casualties. The Saint Francis Health System campus also went on lockdown following the shooting at the Natalie Medical Building.

The medical building is known to house a breast health center and an outpatient surgery center.

The attack is one of the latest mass shootings in the United States, coming soon after the high-profile shootings in Buffalo, New York, and Uvalde, Texas.

Biden addressed the nation from the White House following the shootings, and called for Congress to pass stricter gun control measures such as raising the age requirement to buy a semi-automatic weapon from 18 to 21.

“Just over a week ago, there have been 20 mass shootings in America, each with four or more people killed or injured,” Biden said. “That doesn’t count the carnage we see every single day that doesn’t make the headlines,” Biden said after mentioning the Tulsa shooting.

The perpetrator, Louis, was carrying a letter on him at the time of the shooting that “made it clear that he came in with the intent to kill Dr. Phillips and anyone who got in his way.” Louis “blamed Dr. Phillips for the ongoing pain following the surgery,” the chief said.

Franklin said Louis had called the office “several times over several days,” saying he was still in pain and saw Phillips for “additional treatment.” Louis called the office the following day “complaining of back pain and wanting additional assistance,” according to Franklin.

According to a profile on the clinic’s website, the 59-year-old doctor was an orthopedic surgeon focusing on spinal surgery and joint reconstruction. Phillips was formerly the lead physician for Tulsa’s WNBA team.

Dr. Cliff Robertson, president and CEO of Saint Francis Health System, called Phillips a “consummate gentleman” and referred to the three employees who were killed as “the three best people in the entire world.” He added that they “didn’t deserve to die this way.”

According to police reports, William Love, a 73-year-old retired Army sergeant, was taking his wife Deborah to her six-month check-up when he walked into the shooter’s path.

Reports from witnesses claim that Love held a door shut to allow others to escape from the shooter through another door and prevent the shooter from pursuing them.

Daughter Karen Love was with her parents in an examination room at the time.

“As they heard this guy going up and down the hall, they knew it was gunfire,” Karen Love said. “They thought it was someone just shooting people. My dad was trying to hold the door the best he could.”

Franklin commended law enforcement’s fast response to the shooting, with officers arriving just three minutes after dispatchers received the report. Officers made contact with the shooter in less than 10 minutes following the call.

Police believe Louis shot himself less than a minute after the first officers entered the building.

“Our training led us to take immediate action without hesitation,” Franklin said. “That’s exactly what officers do, and that’s what they did in this instance.”

According to reports, there have been 12 shootings since January where four or more people have been killed. Additionally, 76 people were killed in just 12 shootings, not including the shooters themselves.

“I … want to express our community’s profound gratitude for the broad range of first responders who did not hesitate today to respond to this act of violence,” Tulsa Mayor G.T. Bynum, mayor of Tulsa, said at a news conference following the tragedy.