The 21 year-old woman, Wanjiru Kamanda, stabbed her 24 year old boyfriend, Farid Mohammed, to death in Buruburu after allegedly finding a love message on his phone.
Buruburu OCPD Richard Kerich said Mr Mohammed died in hospital while undergoing treatment for the multiple stab wounds on his back, stomach, chest and neck.
Mr Mohammed has since been buried but police are waiting for a post-mortem report on his death.
The woman had also sustained two stab wounds during the incident. She is handcuffed on her hospital bed and is under constant police surveillance.