An Administration Police officer shot an 18-year-old M-Pesa operator then turned the gun on himself in a suspected love triangle at Ndabibi in Naivasha.
The local police boss Samuel Waweru told the Nation that the officer walked into the shop, which was run by the teenager, and shot her.
Mr Waweru said the teen sustained injuries in the Saturday morning incident and is undergoing treatment at Naivasha Sub County Hospital.
"I have been in touch with the hospital administrator and has said the teenager is in a stable condition," said Mr Waweru.
After shooting the girl, Mr Waweru said the officer went back to his house and shot himself dead.
"It seems the officer thought that his alleged lover was dead and then turned the gun on himself," said Mr Waweru.
The AP officer had worked in the Ndabibi station for a little over a year. His body was taken to Naivasha Sub County Hospital mortuary.