Mr Waweru said the transporter's accomplice escaped but that police launched a search.
He said the man was taken to Naivasha sub-county hospital under police watch.
Two other people injured in the incident were taken to Naivasha Level Five Hospital.
In September 2018, police raided the home of a suspected drug dealer and confiscated 11 bags and 80 stones of bhang with an estimated street value of Sh2 million.
Acting on a tip, the officers struck at the suspect’s Kayole homes on the outskirts of Naivasha but the owner managed to escape.