Here is the summary for the middle part of the story:

While the Poloce chief handle the media, his best man, inspector Adebanjo,
was doing the investigation.

The inspector asked questions to Chief Benson' wife, about the document
the invaders wanted. Precious told him that she was not close enough to
hear the full conversation, so she has no idea what the document was about,
but she could tell the inspector where the document was found.
The inspector always asked for a more detailed description of the killer,
the one with the scar. He showed her several photos of known criminals
with scars, but she was unable to recognize anybody.

Amongst the papers of Chief Benson, the inspector discovered that he had
hired a private investigator from the city. The PI indeed confirmed that
he was hired by Chief Benson, for two missions, one business related and
one politically related, and asked for full immunity.

The murder made the national news, and an investigation reporter from a national
newspaper had discovered that Chief Benson have had a secret son from another
woman.

There were 3 possible reasons for the murder that needed to be followed.
The Police chief was not amused: he did not need this two years before
retirement.