So was *spoiler*'s death a suicide?

So was Dylan's death a accident or suicide, what do you think? I got the feeling that the film was trying to say he killed himself despite Fisher saying it was a accident to the police officer by them showing the scene of him clutching his head in pain and standing up looking in the pool between the question and Fishers answer. I liked the ambiguous element and how it added an even more sad interpretation to the Gatsby pool death.