District 4 officers responded to a call for a Cutting at the Central Library located at 1301 Olive around 1:00 p.m. on October 18.
A 31-year-old man told a security guard at the library that he had been stabbed. The security guard called 911 for help.
EMS took the man to the hospital where he was listed in stable condition.
The man told officers that he was walking on Washington when he was approached from behind by a man in a gray hooded sweatshirt who stabbed him in the back.
The investigation is ongoing. Anyone with information is asked to call the Central Patrol Division at 314-444-2500 for a District 4 detective. Anyone who wants to remain anonymous and/or is interested in a possible reward can call CrimeStoppers at 866-371-TIPS (8477).