Vladimir Romanov, a resident of the Kaliningrad Region who worked as an independent taxi driver, was arrested in September on suspicion of committing a series of murders between 2001 and 2005. At least 10 girls and young women, aged 11-20, were found dead in four districts of the region.
"Vladimir Romanov, 56, accused of killing 10 girls, committed suicide in the pre-trial detention center," a prosecutor's office spokesman said. "He hanged himself late last night, October 11, in a solitary cell."
The suspected killer, who previously served a prison term for raping a young girl, was arrested on a tip from the father of one of his victims, who managed to escape.
The spokesman said that Romanov attempted suicide even before prosecutors filed charges against him, and that prison officials were instructed to monitor him closely.
Kaliningrad prosecutors have launched a probe into the circumstances of the suicide, he said.