Police and the family of slain Wells Fargo Human Resource Manager Willis Onyango Ayieko plan an autopsy on the body on Tuesday October 29.
Detectives said this will also form the basis of the case detectives are preparing.
Officials said detectives have a clue on the motive and hope to make arrests soon.
The autopsy will be conducted Tuesday in Nairobi where the body was moved to as investigations go on.
Police are holding two Mpesa agents who operate in Siaya after it emerged the killers of Ayieko withdrew money from his mobile phone through mobile banking system.
The agents are supposed to help detectives identify the men who withdrew at least Sh100,000 in different locations in Siaya between October 19 and 20.
Police are investigating murder and robbery with violence in connection with the incident.
Police want talk to his colleagues at the current work station and former ones as part of the probe into the murder.
Ayieko was a licensed gun holder. His pistol with 14 bullets was among valuables stolen from him.
Ayieko’s body was discovered in Mungowere stream in Yala, Siaya County on October 23 at 2pm.
The family had reported he was missing on Monday October 21.
Police said the body was decomposed when it was discovered by a student.
It had bruises on the face and stomach indicating it was dragged on a rough surface.
The body was half naked and seemed to have been tortured elsewhere before being dumped at the scene.
The killers then drove his car to Sabatia area, in Kakamega, which is few kilometers away and abandoned it on the roadside.
Ayieko went missing last Friday on October 18 after attending a burial vigil event in Gem, Siaya County.
He had stayed until about 10 pm before he left the funeral never to be found alive.
The family said he had left his home in Nairobi and informed them he would be back on Monday as he was to attend two funeral events.
He flew out of Jomo Kenyatta International Airport to Kisumu at about 1 pm and picked up his four-wheel drive car that was waiting for him.
After running few errands in Kisumu, he drove to a funeral vigil in Gem, Siaya County.
His car had a dash camera and tracking devise.
Investigators have pieced together Ayieko’s last moments before his body was discovered almost five days after his abduction.
Detectives say preliminary findings show whereas Ayieko’s four wheel drive car had a working dash camera, it was switched off or disabled on Friday October 18 night.
This, according to police shows those who took him were aware of the camera and made efforts to disable it or hide their identities.
Two men who dumped the car in Sabatia few kilometers away from where the body was found wore caps and never raised their heads while leaving at the scene.
They parked the car next to a petrol station and opened its bonnet to suggest there was a mechanical problem before walking away carrying a bag.
The bag is believed to have been containing Ayieko’s personal belongings and other valuables.
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