The rifle which had been stripped had a magazine loaded with 20 rounds of ammunition.
Earlier, Omuse had been overheard saying that he would travel to Thika to deal with his girlfriend whom he alleged had defrauded him Sh 900,000 that he had borrowed as a loan.
Efforts to trace the warden in Meru became fruitless, after he disappeared from the prison, where he had been assigned sentry duties.
The last eyewitnesses who saw Omuse in Meru, told detectives that they had spotted him on a motorbike.
In a bid to save the girlfriend’s life, detectives from the Special Service Unit supported by their Crime Research and Intelligence Bureau counterparts, immediately swung into action.
They managed to trace the girl in her house located at Kisii estate in Thika town and immediately moved her to safety.
The detectives then laid an ambush in wait for Omose who arrived on Wednesday and using a spare key, gained entry into the house.
He assembled the firearm and made a call to the girlfriend who is a fourth year student inquiring on her whereabouts.
The detectives immediately moved in and without firing a single shot, arrested Omuse and recovered the firearm loaded with 20 rounds of 7.62 mm caliber, which had been hidden beneath a couch.
“The DCI strongly warns and cautions the female youth particularly those in the universities, colleges and other tertiary institutions to be wary of predators whose bond of love is premised on monetary cords that are meant to temporarily win their affection,” the DCI said.