MOSCOW (AP) – Relatives have begun the grim process of identifying loved ones killed in the wreck of a train Russian authorities say was blown off the tracks by a terrorist bomb.

Investigators are trying to determine who was behind what would be Russia’s deadliest terrorist attack outside the North Caucasus provinces in five years.

Officials said Sunday that at least 25 people were killed and more than 100 injured when the rear three cars of one of Russia’s fastest trains went off the tracks between Moscow and St. Petersburg late Friday.

Authorities had put the death toll at 26 on Saturday but Russian news agencies said they revised it down to 25. Relatives were identifying victims at a morgue in Tver, a city near the wreckage site.