Samy Bengio, head of the internet giant’s AI ethics group until the controversy broke which led to the departure of two female leaders, resigned on Tuesday. Bengio announced his exit in an email to the colleagues. His last working day will be April 28. Bengio joined Google in 2007 and is an expert in a type of AI known as machine learning. It may be recalled that Timnit Gebru and Margaret Mitchell, the ousted Ethical AI co-leads, had reported to Bengio.