Oklahoma City police say they have found no evidence that the death of Aubrey McClendon, one of the pioneers of the US shale gas revolution, was anything other than accidental.

Mr McClendon was killed when his SUV crashed into a concrete pillar under a bridge at high speed. He was not wearing a seat belt and had veered across the road before the crash, leading to speculation about the incident. He died a day after he was indicted on charges of conspiring to rig bids for drilling rights, writes Ed Crooks in New York.

In a statement, the police said they had carried out both an accident investigation and a homicide investigation into his death, and had “found no information or evidence which would compel us to believe this was anything other than a vehicular accident.”

Mr McClendon founded Chesapeake Energy in 1989 with $50,000, and built it into the second-largest gas producer in the US, but was forced out in 2013 by a clash with the company’s board.

He was 56 when he died.