The top executive at Channel 4, the British network that helped propel Russell Brand to fame, has apologized to a former employee after an internal investigation found that a “serious and concerning” allegation she made against the disgraced comedian was mishandled. The probe was launched last year after Brand was accused of raping, sexually assaulting, and emotionally abusing multiple women in a joint investigation by the channel’s Dispatches team, The Times of London, and The Sunday Times. Brand, 48, has repeatedly denied wrongdoing. The inquiry’s report, released Thursday, found “no evidence” that channel bosses were previously aware of any of the allegations against Brand revealed by the investigation. But the report also stated that, after the Dispatches documentary aired last September, a former staff member had come forward with a “worrying” claim about Brand’s behavior towards her in the 2000s. “That allegation was not passed up Channel 4’s senior management chain, nor investigated as it ought to have been” when it was “originally made in 2009,” according to the report. Alex Mahon, the broadcaster’s chief executive, said in a statement that he had apologized to the former staffer.