Ricardo and Consuelo

One thing about this movie is that the psychological make-up of the main characters, Ricardo and Consuelo,they are left without explanation to the audience.Apart from that, their motivations are not clear.
Why did Consuelo kill Marina? Why did Ricardo wanted to kill her instead of telling the police officers who have identified the right person? What made Comfort become so passionate about Ricardo after getting involved with him on a one-night stand when it was clearly shown in the movie that he has no interest with her whatsoever? There are too many unanswered questions in this movie especially when it comes to the qualities of the main characters.