Kevin Kang'ethe was detained pending extradition to the United States over the death of Margaret Mbitu, whose body was found in an airport car park last year but slipped out of a police station last week.
"We have re-arrested the suspect and he is now in custody," Nairobi police chief Adamson Bungei said.
The police chief said Kang'ethe was hiding out at a relative's home on the outskirts of Nairobi, where he was found late Tuesday after a days-long manhunt.
"He will now be taken to court to face charges of escaping from lawful custody as he awaits extradition," Bungei said.
The escape had left police red-faced, with Bungei describing the events at the time as "embarrassing."
U.S. and Kenyan authorities had launched a manhunt after Mbitu was found stabbed to death in a car park at Boston's Logan airport in November.
An arrest warrant was issued for Kang'ethe after he fled the United States for his native Kenya, where he was arrested in late January.
Police said the suspect, who media reports variously said was aged 40 or 41, had been removed from his cell on Wednesday last week for a meeting with his lawyer, when he ran away.
At the time of the escape, the station commander was chairing a meeting with anti-crime personnel in her office, it said, adding that officers gave chase but were unable to catch Kang'ethe.
Four police officers, two relatives and the lawyer were arrested in connection with his escape and remain in custody.