The Solomon Islands assistant police commissioner, John Homelo, says the investigation into the killing of Sir Frederick Soaki is a slow process because some people fear for their safety.
Sir Frederick was assassinated three weeks ago in Auki and while police have indicated they have a suspect they have been unable to arrest him.
Mr Homelo say the suspect is a regular police officer, who may be armed and is hiding in bush near his village.
He says the people in the suspect's village have been questioned.
"Some fearing their security, so not much assistance, but there are others that assist the police. It seems that information is flowing in slowly."