A 23-year-old woman in the Russian city of Nizhny Novgorod was kidnapped, raped and locked up in a cellar for nine days, investigators said on Saturday.

Russian authorities said that a 39-year-old male suspect had been detained.

The 23-year-old reportedly agreed to meet the suspect after they met on a dating platform, according to the Russian-language news site Meduza.

At the meeting, the suspect threatened her with a knife and brought her to his basement, the woman told the police.

"Thanks to good investigative work" the woman was eventually found, the authorities said without providing further details.

The 23-year-old local woman left home on the evening of August 24, Meduza reported. The woman's relatives contacted the police after she did not return home, prompting a criminal investigation.

Suspect's wife said he disappeared

Police found the 23-year-old in a basement in the Prioksky district of Nizhny Novgorod, a city of 1.25 million people some 400 kilometers (250 miles) east of Moscow.

Investigators released a video of the basement showing it consisted of several rooms, including one with a bathtub, toilet and bed.

Citing a law enforcement source, state media RIA Novosti said that the cellar the woman was kept in was rented and not owned by the suspect.

According to Russian media  reports, the suspect's wife announced her husband's disappearance on social media on September 1, asking for help in finding him before he was taken into custody.

The DPA news agency contributed to this report.