I've had 4 interviews in the same week. The first one was an interview with the HR. The second and the third one was a general interview with the leads and the produce. The last one was an interview with the HR again, in order to discuss about the offer and etc before the contract agreement.

The interview came in three stages. First with HR, about the role and why you want to work there. Then with some department heads about your experiences. Then with people you'll be working with about your skills/experiences.