Investigators have ordered police to detain the captains of two vessels that survivors from a sunken riverboat said passed them without stopping to help.
Investigative Committee spokesman Vladimir Markin said the two captains would be held for questioning following the sinking of the Bulgaria tourist boat with 208 people on board on July 10 in the Volga River.
Survivors said they watched two commercial vessels pass by as they struggled to stay afloat.
One man said he and other survivors waved their arms repeatedly to no avail, and people on the passing craft reportedly snapped cell phone photos as they went by.
The confirmed death toll reached 114 on Friday. Emergency officials said divers had searched all accessible parts of the boat, which sank swiftly to the bottom.
Another 15 people were still missing and feared dead, and 79 survived. All but a few of the survivors were rescued by another tourist boat that came along more than an hour after the Bulgaria sank during a rainstorm.
The sinking of the overcrowded, 56-year-old boat rekindled concerns about the negligence and corruption that leads to fatal accidents in Russia and the condition of boats, planes, factories and facilities built in the Soviet era.
"Unfortunately, we cannot replace our whole fleet of riverboats and seagoing ships in a single year or several years," President Dmitry Medvedev said.
"Frankly speaking, for 20 years not a single vessel has been produced or purchased," he said. The Bulgaria was built in 1955 in Czechoslovakia.
Medvedev said in televised remarks that the authorities must ensure that anyone to blame for the disaster is held accountable and punished severely enough to set an example.
"This means not just those who stamp documents, not scapegoats, but also those who organized the cruise," he said.
Authorities have arrested the head of the tour company that leased the Bulgaria, as well as a river transportation inspector.