Embakasi DCI boss Simon Mutia Mwongela spent the weekend in police cells following the shooting dead of a night guard in Kayole, Nairobi.
The senior superintendent of police is expected in court on Monday to be charged with murder.
He was Thursday grilled by his seniors and recorded a statement ahead of Monday’s sessions.
Seven witnesses of the incident recorded statements before Mwongela was locked up at the Kileleshwa police cells for the weekend because Friday was Idd Ul Fitr holiday.
The police boss is said to have been engaged in an altercation with a guard at the Night Square Hotel in the area, prompting Mwongela to shoot him.
He shot Lapaja Topiwo, 23, twice in the chest killing him on the spot after their quarrel.
Witnesses told police Mwongela had been brought to the facility at about 2am on May 14 and slept on the lounge for two hours before he woke up.
He was dropped there by his driver who is a police officer so that he could sleep as he seemed tired.
According to police and witness accounts, when the police boss woke up he demanded to know where his car was.
The staff there told him he had been dropped by his driver. But he did not listen to that and went for his Jericho pistol before cocking it, which forced the staff to scamper for their safety.
The staff locked themselves behind a metal grill at the hotel, which has lodgings upstairs.
It was at that point they said they heard gunshots and on checking they found the guard lying in a pool of blood.
Police were called and collected the body and two spent cartridges from the scene.
Mwongela was later disarmed and arrested.
Inspector General of Police Hilary Mutyambai said he had ordered investigations into the incident.
“He has been arrested for, among others, a probe into murder and misuse of his weapon,” he said.
Nairobi deputy head of DCI Moses Ndindi visited the scene as he ordered the detention of Mwongela.
He said they would take Mwongela to court under a miscellaneous application to detain him for more days as investigations go on. Colleagues described Mwongela as one of the best officers in the service.
Incidents where police are arrested for misusing their weapons and causing deaths while on duty have been on the rise.
The service has internal mechanisms to handle such incidents to punish officers perceived to be rogue.
Dozens of cases are pending in courts where police officers have been involved in shootings that left some victims dead and others with serious wounds.
Two police constables charged with killing a businesswoman at City Park two years ago were last week found guilty of manslaughter.
Police constables William Chirchir and Godfrey Kirui were charged with the death of Janet Waiyaki on May 20, 2018, while she was in a car with her nephew, Benard Chege.
Another police officer was last month arrested after he shot dead a guard and taxi driver in an altercation in Utawala area, Nairobi. He is facing murder charges.
Edited by Henry Makori