A woman in Juja, Kiambu county on Friday morning discovered a G3 rifle and 15 rounds of ammunition hidden in her shamba near Ndarugu academy.
According to Juja OCPD Simon Thirikwa, Consolata Onyango was digging her shamba when she hit a hard object.
"The woman was digging when her jembe hit a hard object," he said.
The OCPD said when she removed the soil, she was shocked to see a sack in which she found the gun and a crowbar.
She informed a local chief Muiruri Muchui who in turn reported to the AP post in Witeithie.
The officers led by inspector James Dawai and Corporal James Kinyua collected the weapon.
Thirikwa commended the woman for giving the vital information.
He said police would investigate if the gun has been in use in the spate of robberies in the area.
The gun was taken away for ballistic examination.