Basic Instinct : Why was Nielson…(Spoiler Alert)

Why was Nielson…(Spoiler Alert)

Does anyone know why Nielson was investigating Beth a year before the murders took place? I remember when Michael Douglas went to pull the police report, the other policeman said Nielson had it for a year and wanted it back -

Thanks in advance...

Re: Why was Nielson…(Spoiler Alert)

I seem to remember that he was a 'friend' of Catherine's and she asked for the file. Just part of her evil, sick, twisted plot to write yet another best-selling novella based upon her murderous escapades.

Of course I may be way off here...

Re: Why was Nielson…(Spoiler Alert)

Thanks for the response, however, Nielson had the file for a year according to the police officer and wanted it back - Doesn't make sense why he wanted the file on Lisa Hoberman a year before all of the murders happened. Nick ever went to the fat policeman that was washing the police cars and was asking him about it - Doesn't make sense -