(MOSCOW) -- Two men have been detained in connection with Tuesday's subway crash in Moscow that left at least 23 people dead.
A track foreman and his assistant are suspected of criminal negligence. Authorities say they failed to install a switch properly which may have led to the crash.
The exact cause of the accident is still a mystery. Investigators are also looking into whether that switch was defective.
Meanwhile, on Wednesday, Moscow observed a day of mourning as the death toll continues to rise.
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