Mattia Binotto confronted Christian Horner after the US GP and threatened him with legal action, according to the Spanish source Motorlat.
Other photographic evidence emerging in the wake of the Austin race appear to back up correspondent Yhacbec Lopez's claim about the Ferrari chief's fury.
The normally calm Binotto was enraged after Austin when Red Bull-Honda driver Max Verstappen said Ferrari had been caught "cheating" with its engine.
"I was standing outside the Red Bull hospitality," Lopez claims.
"When (Red Bull boss) Horner had finished with English journalists, Mattia began an exchange of clear and blunt views.
"He spoke firmly to Horner and what I managed to hear was a warning about legal action. Horner explained that he (Verstappen) only shared an opinion, and Mattia replied in a strict tone.
"From what I saw, it is clear that Binotto is far from being the good natured boss that many think he is," Lopez added.
