Police on Sunday killed five suspected criminals at Dandora dump site in Nairobi.
The officers who were acting on a tip-off raided the shanty which they suspected was being used as a hideout by drug traffickers.
According to a police report, the suspects started shooting at the officers as they approached. One of the suspects managed to escape.
A Ceska pistol, two homemade guns and 14 rounds of ammunition were confiscated at the scene. The Ceska pistol did not have a serial number.
Other items seized were a sack of bhang, 184 rolls of bhang, a claw bar, 32 sachets of alcohol, a knife and four pairs of scissors.
Their bodies were taken to City mortuary.
In Kiambu on Saturday, police recovered a Berretta, Ceska and Flare pistols and 150 rounds of ammunition in an abandoned house in Ruiru.
Kiambu Directorate of Criminal Investigation boss Amos Teben said investigations into the owner of the firearms have started.
"The weapons seem to have been licensed and we want to know more before we take action," Mr Teben said.
The firearms are being subjected to ballistic tests.