A government report released by the inquest led by Dr S W Mwangi in June revealed that the late Senator died of massive bleeding caused by high blood pressure.
The report explained that the massive bleeding could have been due to excessive ingestion of some substances that include caffeine.
The deceased's Personal Secretary, Stellar Mwendwa, told the inquest that her boss had complained of fatigue and had lost weight before he died.
Kilonzo Junior and a farm worker, however, stated that the deceased had not complained of any illness before he died.
Mr Kilonzo died at his ranch in Maanzoni, Machakos County in April 2013.
The former Lawyer's body was found tucked in bed with foam in the mouth. There were also indications that he had vomited.
Tests conducted on the vomit at the Government chemist, however, all showed no sign of any known toxins.