The late Sergeant Kipyegon Kenei died from a single contact gunshot wound, postmortem results have revealed.
The postmortem showed that Kenei died a day or two before he was discovered.
The results revealed the body had no marks of struggle by the officer.
No other wound except the bullet entry one under the chin and its point of exit at the forehead.
The team says it's not conclusive whether it was homicide or suicide and will visit the scene on Thursday to piece together the final details.
The postmortem revealed that the gun was placed at skin contact under his chin.
Kenei who was attached to Deputy President William Ruto's Harambee Annex was found dead after missing for two days.
His body was found with a bullet wound in his head at his house in Imara Daima's Villa Franca estate.
Kenei's family had ruled out the possibility that the AP took his own life.
His elder brother Emmanuel Kenei said Friday that the last time they met, the officer was his usual self.
The family said they are considering hiring private investigators to probe his death.
They have protested how the police are investigating the circumstances under which he was found dead in his Imara Daima home.
The family want their private investigators to conduct an independent probe before the police "interfere" with the scene of the crime.