No doubt they already are... also, between the DTCC, Signature and FINRA, they have probably determined exactly how many shares were (illegally) added to the o/s and into the market..and should know how much of the dividend was valid.
So, if COR and any other clearing houses left high and dry because the perp's have absconded with the spoils, then it's quite likely that the FEDS are on the lookout for them and the money. And a clawback becomes more than a possibility...