Russian authorities have detained a man suspected of murdering dozens of elderly women in the republic of Tatarstan and nearby regions nearly a decade ago.

Unofficially known as the “Volga maniac,” the murderer has been linked to the killings of anywhere from 19 to 32 female pensioners, most of whom were strangled to the death between March 2011 and September 2012. Investigators said that the suspect may have posed as a social services worker to enter the apartments of the women, who were between 75 and 90 years old and lived alone.

Radik Tagirov, 38, was detained by law enforcement officers in Kazan on Tuesday as part of a criminal investigation into 26 of the murders, the Investigative Committee that probes major crimes said. The committee’s statement said investigators carried out thousands of tests to identify the suspect.

Tagirov confessed following his detention, investigators said.

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