CHICAGO (WLS) -- Chicago police are investigating the carjacking of a woman in the city's River North neighborhood Monday afternoon.The carjacking happened in an open-air parking lot at Huron and Franklin around 5 p.m., a busy area full of restaurants and boutiques.The victim was not physically hurt, but badly shaken up. She said she was ordered to give up her keys by a lone male offender and complied, but not before a parking lot attendant tried to intervene. The suspect then brandished a knife and made his getaway in the stolen vehicle, a black Mercedes SUV.Valya Borisova was among a group of witnesses, including a parking attendant who came to the victim's aid. The attendant was forced to back off after the carjacker pulled a knife."This is just insane because this is considered the best area to live in downtown. It's one of the safest neighborhoods, and to have things like this happen in River North is incredible," Borisova said.Monday's carjacking came on the heels of another River North carjacking at Huron and Wabash, in which armed men stole an Infiniti sedan which would later be involved in a high speed pursuit in Northwest Indiana. Police said officers fired upon the car after the two alleged shoplifters inside tried to run them over.Monday, the victim stayed at the scene for some time giving a statement to police. And Borisova said the carjacker was undeterred by the presence of witnesses."She was like, 'Help me! Help me!' And then a lot of people that were... There was about, I want to say, like five people walking out of work as a group that started screaming 'Help her! Help her!'" she said.