Just scanned through the 99 page document and it looks as if the FBI (prior to it having been completely taken over by leftists as it is now) was keeping tabs on this individual because they felt he was a communist, (Mikva) planted a recording device in a jury room at one point, supported abortion, etc.

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Edit - a couple links on Mikva's spouse --

https://chicago.suntimes.com/2019/1/19/18332353/educator-activist-zoe-mikva-wife-of-abner-mikva-dies-at-90

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https://dailyentertainmentnews.com/breaking-news/zoe-mikva-judge-abner-mikvas-wife/

Just scanned through the 99 page document and it looks as if the FBI (prior to it having been completely taken over by leftists as it is now) was keeping tabs on this individual because they felt he was a communist, (Mikva) planted a recording device in a jury room at one point, supported abortion, etc.