A production source tells us Smollett flew back into the Windy City Sunday, after his weekend show in Los Angeles. We're told Smollett shot scenes for one of the final episodes of the season Monday and did a table read with the cast Tuesday ... security was present the entire time.

Law enforcement sources tell us cops want to speak with Jussie while he's in town as part of their ongoing investigation.

As for where he's staying while in town ... a source close to Jussie tells us he's back at the same apartment complex where he was living at the time of the attack.

Jussie made his first public appearance at a concert at the Troubadour in Los Angeles Saturday, where he very proudly stated, "I couldn't let those motherf*****s win!" The show was supposed to have a meet and greet, which was canceled due to security concerns.

Police revealed Monday they've found additional surveillance footage surrounding the time leading up to and after the incident ... but the new video hasn't been released. Our sources say cops have not found any video of the attack or anyone fleeing after the attack.