One of the suspects shot dead in Muthangari and the other who escaped on Monday were former officers, police have said.
The second suspect shot dead at a private residence, Zacharia Koi, was attached to the Anti-stock Theft Unit.
The other, Constable Fredrick Afande, who was armed with an AK47 rifle and escaped in a white Toyota Probox, is a former General Service Unit officer.
He was recruited into the police service in 2007, deserted duty in 2010, then in April, went back to work but was dismissed the same month.
Information retrieved from one suspect’s mobile phone shows that during the deadly exchange, he called Administration Police officers based at the Kibera DO’s office and another in Mathare.
The firearms recovered — Ceska pistol serial number B064313, Ekol pistol serial number EP-1282250, and Webley Revolver — have been used in the commission of several robberies within the city, police said.
Police investigations reveal that most robberies in Nairobi and its environs are committed by former police officers, but the government has no clear policy to monitor such officers.
Interior Cabinet Secretary Joseph ole Lenku yesterday said the government would come up with a strategy to monitor former officers who were either sacked or retired from the service.
Mr Lenku also urged Parliament to come up with legislation allowing police to use lethal force in certain circumstances.
“Police normally strive for the arrest and prosecution, but many a times this is not possible as the suspects are armed,” said the Cabinet secretary.
While speaking at the Nairobi Hospital where he had gone to comfort the two injured officers — accompanied by Nairobi County commander Benson Kibue — Mr Lenku also called for the speedy amendment to the law that allowed all criminals, irrespective of the crime committed, to be released on bail.
The minister promised to provide the police department with additional protective gear for use in risky operations, especially in Nairobi where there is increased insecurity cases, with at least five robberies per day.
The incident happened just a day after a senior UN official and his wife were robbed on the same Mzima Spring by three armed men as they were strolling. Mr Jaruslav Mandy, a Czech, and the Permanent Representative to UNEP and Habitat told the police that they were confronted by three armed men riding on a motorcycle.
They robbed them of cash and other personal effects before riding away towards Olenguruone Road.
On Sunday night, a driver with the British High Commission and another British journalist were also robbed in separate incidents. George Smith, the journalist, was attacked by armed men at his Karen residence by three men armed with a shotgun.
They robbed his family of cash and other household goods including his British passport before poisoning his dog.
Within the same Karen area, another UN staff was attacked on Saturday night by six armed men who robbed the family of cash and household items, injuring his wife and house help.
Police also say the High Commission driver had dropped a colleague home when he was blocked by two cars. They later abandoned him at Woodley estate. The vehicle, a Toyota Prado, was later found vandalised.