DCI detectives have arrested at least 41 suspects allegedly found transacting in the illegal business at an undeveloped yard behind a petrol station off Lunga Road in Nairobi.
The suspects were arrested as DCI stepped up the fight against illegal trade in adulterated fuel and increased cases of siphoning.
During the raid, five tankers were found at the site.
DCI says over 17,020 litres of diesel, 6,110 litres of petrol, four generators, 30 drums, siphoning pipes and jerrycans were recovered and impounded.
DCI Crime Scene Investigators and Energy and Petroleum Regulatory Authority (EPRA) officials documented the scene.
"Acting on intelligence, the Operation Support Unit team recently deployed to curb the unbecoming trend surrounding the site, rounding up the numbers who were trading with impunity," DCI boss Mohamed Amin said in a statement on the raid on X.
"In the yard were two petroleum trailers both loaded with petroleum products, but whose three compartments were without security seals."
Three other petroleum tankers' registration numbers were also found loaded with some amount of petroleum products suspected to have been siphoned from the trailers.
A car loaded with 50 litres of petrol was also detained.
DCI says documents found in one of the trailers showed the fuel was from a petroleum company depot destined for its petrol station in New Gatitu, Thika.
The suspects are in custody pending arraignment on Monday, April 15.