Siaya Senator James Orengo has said the Malindi home which was raided by police and arms seized is not owned by billionaire Jimmy Wanjigi.
He said they have information that the cache of arms was planted owing to the businessman's association with the National Super Alliance.
Orengo and former Machakos senator Johnston Muthuma told journalists that the raid was political.
Wanjigi backed NASA leader Raila Odinga ahead of the August 8 general election and is said to be still calling shots in the coalition.
"The information we have is that the home raided in Malindi doesn't belong to Jimmy and the cache of firearms were planted," Orengo said.
He spoke at Wanjigi's home in Nairobi's Muthaiga estate when police officers raided the premises on Monday reportedly in search of illicit firearms.
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Orengo, a NASA lawyer, said they had been unable to talk to Jimmy but declined to confirm whether the businessman was in his house.
"We have managed to talk to the wife and father who raised concerns over this illegal act."
"There is no basis for the police to continue being here as they have no arrest warrant. This is an illegal act and points to circumstances aimed at trumping up charges," Orengo said.
Officers from the Flying Squad, Special Crimes Prevention Unit and the Directorate of Criminal Investigations laid siege at the home for over seven hours.
However, after successfully gaining entry into the compound, the contingent was unable to access the luxurious house of the business oligarch.
The officers, who were in six cars, idled within the spacious posh compound for the better part of Monday waiting for Wanjigi to let them in to conduct a search.
Journalists who were alerted of the siege were kept outside the compound but could see the convoy of police cars packed inside.
Private security guards who man the main gate let in a number of family members who walked in including Jimmy's father Maina Wanjigi.
Suna East MP Junet Mohamed and Muhoroni MP Onyango K'Oyoo were also present.
They also condemned the police action as illegal and unwarranted for a "law-abiding Kenyan".
Junet hit out at the Jubilee regime which he accused trying to intimidate Wanjigi because he switched to NASA.
"Wanjigi is being targeted because of his association with NASA. He is being hunted. It appears some quarters are not happy," the legislator said.