Alexander Kim, CEO of Sputnik, a company that organised a guided tour of Moscow’s sewers that resulted in the deaths of all eight members of the group, was detained in St. Petersburg on Tuesday and is to be transferred to Moscow, TASS reported.

The tour in question took place on Sunday, when Moscow saw 40% of its monthly rainfall in just one day, causing widespread flooding and drowning all eight people on the tour. Their bodies have since been recovered, TASS reported.

Russia’s Investigative Committee identified three people who had been involved in organising the tour and a criminal case that could lead to jail sentences of up to 10 years has been opened. Several other people have also been placed on the police wanted list in connection to the case.