MOSCOW (AFP) - Russian investigators said on Saturday (June 19) that they have detained a man on suspicion of murder, after finding the body of a foreign woman the media identified as a missing American student.

Russian news agencies identified the woman as 34-year-old United States citizen Catherine Serou.

Earlier this week, investigators said that a 34-year-old foreign woman who lived just outside Nizhny Novgorod, a city about 420km east of Moscow, had gone missing after getting into an unidentified car.

They said she had moved to Russia in 2019 to enrol in a master's programme in law at Nizhny Novgorod's Lobachevsky State University.

On Saturday, an investigative committee that probes major crimes in Russia said it had found the missing foreign student.

"Today, as a result of a large-scale search operation, the girl's body was discovered," the committee said in a statement, without naming her.

The committee added that the police had detained on suspicion of committing murder a Nizhny Novgorod resident born in 1977 "who has been repeatedly convicted of grave and especially grave crimes".

Investigators said that the woman's last communication before going missing was with her mother just after 6.30pm local time on Tuesday, telling her that she was travelling in a car with unknown people.

Search teams and volunteers had been looking for Ms Serou in a forested area outside the city where her phone signal was last picked up.

On Friday, Ms Serou's mother Beccy told US radio NPR from Mississippi that her daughter had moved to Nizhny Novgorod in 2019 and had sent her a final text on Tuesday evening, saying: "In a car with a stranger. I hope I'm not being abducted."

Mrs Beccy Serou said: "And that's the last thing she wrote."

Mrs Serou added that she was hopeful for her daughter's safe return because she was a former US Marine who had done a tour in Afghanistan, according to NPR.

Mrs Serou said that her daughter had been in a rush to return to a clinic where a payment had not gone through and so may have hitched a ride with a passing car rather than waiting for her Uber.

The US embassy in Russia did not immediately respond to a request for comment.

According to her mother and to reports in Russian media, Ms Serou had planned on returning to the US to pursue a career as an immigration lawyer.