[4] He supervised for a time the comital administration in the counties of Roussillon and Cerdagne on behalf of Alfonso II, who was also count there.
[5] Berenguer was assassinated by a relative, Guillem Ramon I de Montcada, his niece's husband.
In a letter to the suffragans of Tarragona, Pope Celestine III detailed the crime, especially heinous because proprius homo fuisset archiepiscopi, "he was the archbishop's man", i.e. vassal.
By that time Berenguer "appeared in the eyes of the partisans of the Cabrera–Castellbò band as the principal inspiration in royal politics.
Pope Innocent III delegated his case to three cardinals—Nicholas of Tusculum, Pelayo of Albano and Ugolino of Ostia—who imposed a strict penance on him.