ST. PETERSBURG, Russia — In June, a high school student discovered a decapitated and dismembered body in a swimming hole on the Mga River just outside St. Petersburg, Russia’s second largest city. Using the serial numbers of Irish-made breast implants found on the body, police identified the victim as 23-year-old Jamshid Hatamjonov, a transgender sex worker from Uzbekistan who preferred the name Tamara. She had disappeared in St. Petersburg five months earlier, on the night of January 12-13. Last week, a court sanctioned the arrest of 53-year-old actor and theater producer Yury Yanovsky in connection with the case. Investigators allege that Yanovsky was Hatamjonov’s last client and that he killed her in a St. Petersburg hotel using a knife and a saw.