A man stabbed two people at the Smith’s Marketplace grocery store in downtown Salt Lake City before being subdued by a bystander.

The attack took place around 5:30 p.m. in the parking lot of the store at 455 South and 500 East. According to a witness, it appears one man was stabbed in the side of the head and another was stabbed in the stomach. The exact condition of the victims is unknown, but police believe the injuries are very serious and possibly critical.

Police say a bystander with a concealed carry permit witnessed the attack and stepped in to keep it from escalating.

“(The bystander) was suspicious of what might be going on, and when he saw the stabbing, he just drew his pistol and challenged the individual,” which caused the alleged attacker to lie down on the ground, Brian Purvis with the Salt Lake City Police Department said. By the time police officers arrived on the scene, the man was subdued and is now in custody.

The attacker apparently bought the knife inside the store.