The aircraft, a Eurocopter AS350, went down in a forested area and caught fire on impact, killing all six people on board.
As tributes were paid to the fallen MP, Onyonka took the microphone and addressed the congregation with strong words.
He made it clear that he did not have evidence to support his claim but said he believed there could be more behind the tragic incident.
“I believe, even though I do not have the evidence, Ng’eno has been killed because he refused to sign the land which has got rare minerals kule Kilgoris,” Onyonka said.
His remarks drew attention from both the congregation and leaders present at the service.
Among those in attendance were former Deputy President Rigathi Gachagua, former Interior Cabinet Secretary Fred Matiang’i, Wiper party leader Kalonzo Musyoka, and Narc-Kenya leader Martha Karua.
Onyonka went further to speak about the dangers that some politicians face while carrying out their duties.
Referring to remarks made by another leader, he said some of them live knowing that death could come at any time because of the stands they take.
“Some of us tunatarajia tutakufa wakati wowote. I can tell you that. What we are doing si kazi ya rahisi hivyo.
But we know kuna nchi ambayo lazima itetewe, na hiyo inchi inaitwa Kenya,” he said.
His words painted a picture of a political environment filled with tension and risk.
While he did not provide proof to support his claims, his statement added a new layer of speculation around the tragic death of the Emurua Dikirr MP.
Ng’eno’s sudden passing has left his supporters and colleagues in shock. He was remembered at the service as a bold and outspoken leader who stood firm on issues affecting his constituents.