Since the claim that they closed their position in itself would potentially influence the market to their benefit, I don't see a reason to trust their statement.
Either way, it would be illegal to say that they closed their position for the sake of influencing the market. The SEC really doesn't play around with that type of thing in such a high profile case
Melvin Capital also said a day earlier that they do not give out comments on their positions and trading.
https://www.reuters.com/article/us-melvin-fund-evotec-de-idU...
Since the claim that they closed their position in itself would potentially influence the market to their benefit, I don't see a reason to trust their statement.