"You had police officers being shot at. Four were shot. You had firefighters responding to businesses being burned and they were assaulted and blocked from getting, you know, to do their job to protect us," Schmitt said. "You had a retired African-American police officer who was protecting property [and] was shot and killed. It was broadcast live on social media. You had businesses burned by the assault on the police officers."
Schmitt vowed that he would work with federal prosecutors to "bring these people to justice."
St. Louis Police Chief John Hayden told reporters earlier Tuesday that two officers were shot in the leg and one was shot in the foot. The fourth was shot in the arm. Hayden said they were hit by gunfire while standing on the side of a police line amid protests in the city.
Meanwhile, authorities say looters shot and killed retired St. Louis police captain David Dorn, 77. The St. Louis Post-Dispatch reported that Dorn was shot in the torso at about 2:30 a.m. Tuesday and died on a sidewalk in front of the looted shop, Lee's Pawn & Jewelry. The paper also reported the shooting was recorded on Facebook Live.
Schmitt accused the demonstrators of going beyond peaceful protests over the death of George Floyd last week.
"I think one thing to make really clear here is that, you know, the First Amendment, our God-given right to demonstrate, to be heard, to express ourselves, is protected and people out there are doing that," he said. "But last night in St. Louis, that crossed the line and there were some folks who took advantage of that situation.
"[We had] a highway patrolman who was hit in the helmet with a bullet. Again, somebody shot and killed defending property on Facebook Live. This is unacceptable."
"And to live in a civilized society, we all expect more," Schmitt added. "Our laws mean something and they need to be enforced."
Fox News' Robert Gearty, David Aaro and Edmund DeMarche contributed to this report.