When it was shown to me that there would be a plot (mēnutheisēs moi epiboulēs esesthai). Two constructions combined; genitive absolute (mēnutheisēs epiboulēs, first aorist passive participle of mēnuō) and future infinitive (esesthai as if epiboulēn accusative of general reference used) in indirect assertion after mēnuō (Robertson, Grammar, p. 877).
Charging his accusers also (paraggeilas kai tois katēgorois). First aorist active participle of paraggellō with which compare mathōn above (Act 23:27), not subsequent action. Dative case in katēgorois.
Before thee (epi sou). Common idiom for “in the presence of” when before a judge (like Latin apud) as in Act 24:20, Act 24:21; Act 25:26; Act 26:2. What happened to the forty conspirators we have no way of knowing. Neither they nor the Jews from Asia are heard of more during the long five years of Paul’s imprisonment in Caesarea and Rome.