Former Cabinet minister Simeon Nyachae's family hired a former police officer to dig into Margaret Chweya's life.
Sebastian Omboto has also filed an affidavit acknowledging that he was the man behind the investigations.
Omboto says that he is a member of the Kenya Association of Kenya Investigators and has previously worked with the Kenya National Police Service and private security firm, Wells Fargo.
"I was retained by the Nyachae family to undertake the investigations into Margret Kerubo Chweya's various assertions as set out in her affidavits and witness statements. The said assertions touch on allegations that she was a customary wife to the late Hon. Simeon Nyachae and they had three children together- Rodney David Chweya, John Chweya and Patricia Chweya," he says.
According to him, Chweya was married to George Gordon Odero on April 11, 1987, in Clark County, Nevada, US, under marriage certificate number B681250.
He adds that she was also married to James Leroy Totten on July 22, 1989.
Omboto states that he got the information from an investigator from the US.
At the same time, the investigator narrates that he established that Chweya had a stepmother called Agnes Kemunto Chweya.
He claims that Kemunto knows about Chweya's marriages in Kenya.
"I interviewed Agnes Kemunto Chweya and found out that Margaret Kerubo was married to Jacob Machuki Mokaya in 1973 who sired their first born son Samuel Onyancha."
Omboto states that Samuel Onyancha is also Rodney Chweya.
He then went to Nairobi registry of births and retrieved a birth certificate indicating that Machuki is Onyancha's father.
"The father of Samuel Onyancha, Jacob Machuki, confirmed the said Samuel Onyancha was his first-born son."
The investigator, in his affidavit before High Court, states that he also obtained a birth certificate of John Paul Chweya, which allegedly revealed his father was Michael Pondo Migowa.
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"I further established a baptismal certificate no. 442 contained in the baptismal register of 1980 by the Archdiocese of Nairobi depicts the father of Margaret Chweya's son- John Paul Pondo as being Michael Pondo and not the late Hon Simeon Nyachae," he states.
According to him, Chweya's stepmother told him that she received dowries from the two men.
He also interviewed Nyachae's brothers Benjamin Masakara and Hezron Omurwa Nyandusi. The two, according to Omboto, are co-chairs of Musa Nyandusi family.
"They confirmed that Margaret Chweya was never married under customary law to the late Simeon Nyachae."
Omboto adds that the community would have known that Nyachae was marrying Chweya.
Some of those who Omboto allegedly interviewed was Willy Isaboke. The man, in a document also filed in court, claims he is Chweya's cousin. He states that he knows Chweya was married to Machuki but not Nyachae.
The investigator also claims that Kegati Location chief, Eric Ratemo, denied ever meeting Chweya.