Alexei Burkser was found dead with ‘signs of suicide’, said investigators.

The former head of a giant Siberian diamond mine was found dead in his prison cell a day after being charged over the deaths of miners trapped by flooding, investigators said Tuesday.

Eight miners died after water leaked into the Mir mine owned by state-controlled diamond producer Alrosa in 2017. Their bodies were never recovered despite weeks of searches.

The mine’s head, Alexei Burkser, and the chief engineer were fired after the accident.

Burkser was found dead with “signs of suicide” in a jail in the northern Yakutia region where the diamond mine is located, investigators said.

On Monday, they said Burkser, along with the former chief engineer, had been detained in custody and charged with breaching mining safety rules leading to multiple deaths, which carries a maximum jail term of seven years.

Investigators noted the men failed to halt work in the mine despite knowing water was leaking through.

Located in the city of Mirny, the diamond mine is one of the biggest man-made holes in the world.

It is more than a kilometre (0.6 mile) in diameter and 525 metres (1,700 feet) deep, almost the equivalent of two Eiffel Towers placed end to end.

The mine has been shuttered since the 2017 accident.