Why would a person being investigated still have access to the database?!?
Also, in addition to my previous post, in the actual article (my emphasis):
A serving Metropolitan police officer who illegally accessed a police database to monitor a criminal investigation into his own conduct has pleaded guilty to crimes under the Computer Misuse Act
I read this to mean that he didn't have access to the database, but either used someone else's access, or otherwise hacked into it. The CMA, as far as I understand it, covers unauthorised access to computer systems.
What I don't understand is why he hasn't been sacked - the Met should take this sort of misconduct seriously, especially since it will have been made abundantly clear to him what access officers have to the various police databases, and what they are allowed to use them for.