In a personal essay, actor Leonard Roberts broke his silence about his 2007 firing from Heroes, citing racism and a conflict with his former co-star, Ali Larter.

In response, the 44-year-old actress issued a public apology to her former co-star. NBC, which co-produced and aired the hit sci-fi series between 2006 and 2010, have not responded to the actor's claims, made in Variety on Wednesday, Dec. 16. Variety corroborated Roberts' account with 10 people who either worked on Heroes at the time or were contemporaneously familiar with his experience on the show.