A person was carjacked at knifepoint Monday afternoon in the River North neighborhood.

A man armed with a knife approached the victim as she was getting into her parked SUV at 4:48 p.m. in the 300 block of West Huron, according to Chicago Police. He demanded the key to the vehicle and, fearing for her life, the victim handed it over.

A male who saw what was happening tried to help the victim, but he backed away after the suspect swung the knife at him, police said. The suspect then drove away in the black Mercedes.

The suspect was described as a black man between 30 and 45 years old, standing between 6 feet and 6-foot-3 and weighing between 150 and 200 pounds, police said. He was wearing a gray hooded sweatshirt and a bright green winter cap.