I don't know I just don't want to speculate until more information comes out and everyone seems to have already jumped on the bandwagon.
And this is exactly the kind of obfuscation which leads to delays in people coming forward - maybe we're looking for two really tall women? Nope, don't know anyone like that, nothing to report. When in reality the overwhelming odds are that the police are looking for two men, who may or may be dressed as women. The reasons for them dressing as women is frankly irrelevant - it may be a disguise, it may be because of how they "feel" - at the point where a serious crime has been committed, the focus has to be on accurate description. How the perpetrators feel about being called men is neither here nor there.