Richard le Bret

One of the four murderers of Thomas Becket, Archbishop of Canterbury.

At this time, we have him attached to Simon le Bret, on the authority of Wikipedia, which is citing (through an intermediary) Collinson's history of Somerset from 1791. https://en.wikipedia.org/wiki/Richard_le_Breton

Medlands, however, finds no primary evidence for the connection; the connections amongst the various le Bretons at the time are wholly unclear; One came into England with William the Conqueror, but the line cannot be traced. See https://fmg.ac/Projects/MedLands/enguntac.htm#_Toc21079002