According to preliminary data, on August 24, the teenagers went to the bus station in Leninsk-Kuznetsky to see off a friend.
After that, they stopped communicating, RIA Novosti reports.
Investigators worked out the circle of contacts of teenagers, checked their close relatives, interrogated sellers of outlets, near which the disappeared were standing before disappearing.
The place of the last stay of the teenagers was also examined, the recordings from CCTV cameras were viewed. Investigators established in which direction the teenagers left the bus station.
Earlier in the Perm Territory, the body of a ten-year-old girl who disappeared the day before was found with signs of violent death.