https://www.dailywire.com/news/donald-trumps-first-wife-was-under-fbi-counterintelligence-investigation-report
The “secret” files said that in 1989 the FBI recommended opening an investigation into Ivana Trump based on information that bureau received from a confidential source. The FBI report noted that the allegations could have stemmed from “jealousies of her wealth and fame.”
Much is still not known about the two-year investigation other than it involved the FBI’s counterintelligence division and was deemed “highly sensitive.”