Two reporters from The Nation - Cellestine Olilo & Bernard Rotich - have painstakingly retraced Kelvin Kiptum's final hours, even looking at CCTV footage and talking to the people who waited on him at three different bars/restaurants.
You can read it here:
It's worth noting that while his father a few months ago said that Kelvin had never had a drop of alcohol that is not true. Kiptum had two beers at the first establishment which he left around 7 pm (He died just before 11 pm). There is no mention of him drinking alcohol at the final two places and the waiter at the final establishment, where they closed the door in a VIP room, said he didn't order anything to drink at all. The toxicology reports haven't come back yet.
The article also includes this line, "The waiters' accounts are that by the time Kiptum was leaving, he was sober, and his gait was steady."