A former JPMorgan and Citigroup trader, who is currently a star manager at hedge fund giant Brevan Howard, has been named in a UK court as an alleged co-conspirator in what prosecutors call a scheme to manipulate interest rates.

The trader, Alfredo Saitta, and six less prominent individuals were named last month by the UK’s Serious Fraud Office as alleged co-conspirators — but not charged with a crime — during an ongoing trial of other bank employees accused of trying to rig the euro interbank offered rate, or Euribor. The SFO’s allegation about Saitta has not previously been publicly reported.