A decision on whether to reinstate charges against Jussie Smollett[1] in Chicago is getting close ... because we've learned the Osundairo brothers took a trip to the special prosecutor's office.

Sources close to the case tell TMZ ... Abel and Ola met with Dan Webb's team this week because the special prosecutor wanted to hear their full story -- their version of Jussie's alleged attack.

We've obtained video of Abel and Ola arriving for the powwow in downtown Chicago ... and you see them coming in separately to meet with an attorney in Webb's office. The brothers were accompanied by their attorney, Gloria Schmidt.

Our sources say the brothers each spent a couple hours with the special prosecutor's team.

As you know ... the Cook County Grand Jury originally indicted Jussie on 16 felony counts[2] for allegedly lying to cops about the alleged attack[3]. State's Attorney Kim Foxx then dismissed all charges[4] against Jussie in a move Chicago Mayor Rahm Emanuel called a "whitewash of justice."

Now, the special prosecutor is looking into the dismissal ... and Webb has the power to reinstate the charges[5].

Webb is staying on as special prosecutor even amid concerns of a conflict of interest -- Webb hosted a fundraiser for Foxx and made a $1,000 donation to her campaign. A Chicago judge ruled Friday there's no indication Webb harbors any bias.

We reached out to the Osundairo brothers' attorney, but she declined to comment. We also reached

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