Former U.S. Marine Catherine Serou was found dead in Russia after catching a ride with a stranger. Reports said Serou even got a chance to send a text message to her mom during her ride with the stranger, saying that she hopes she's not being abducted.

"In a car with a stranger. I hope I'm not being abducted," Serou reportedly told her mother in a text message.

Catherine Serou is a 34-year-old law student and a Marine veteran from California. On the morning of June 19, she was found dead in a forest outside the Bor suburb, where she lived in western Russia.

A 44-year-old man was arrested in her disappearance an hour after her body was found, New York Post reported. The U.S. Embassy in Moscow said it was closely monitoring the local authorities' investigation and giving the needed assistance to Serou's family.

Regional investigators opened a potential murder case after Catherine Serou disappeared following the text message to her mother, NPR reported.

Investigators pleaded to residents of Bor to provide any clues about the former U.S. Marine's abduction. Police and volunteers searched the forests north of Bor, where the former U.S. Marine's cellphone was last picked up.

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Catherine Serou's Abduction

Catherine Serou's mother, Beccy Serou, told NPR that her daughter had been in a hurry on Tuesday, June 15, to return to a clinic in Nizhny Novgorod, where she made a payment that did not go through.

Beccy noted that her daughter might have jumped into a passing car without waiting for her Uber to arrive. Serou's mother also thinks that her daughter may have started panicking when she saw that the person was not driving to the clinic but instead was heading into a forest.

The 44-year-old local man, who was arrested, was previously convicted of multiple serious crimes. Police said he was cooperating with the investigation, according to an ABC News report.

Local volunteer groups had posted missing person notices asking if anybody had seen Catherine Serou. Around 80 police officers and 20 volunteers from a group, Lynx, had been part of the search for the former U.S. Marine.

Her mother said that Serou moved to Russia to study law in 2019 after selling her condominium in California to finance her studies.

Beccy noted that her daughter enjoyed her time abroad and stayed in touch with her through daily phone calls. She added that Serou loved the university that she was part of.

Catherine Serou enrolled at Lobachevsky University in Nizhny Novgorod for her master's degree in law. Her mother said that the plan was Serou would be going back to the U.S. to pursue a career as an immigration lawyer after her years of schooling in Russia.

Serou served in the Marine Corps and did one tour in Afghanistan before earning a bachelor's degree in design and a master's degree in art history at the University of California, Davis.

Serou was reportedly last spotted on a surveillance camera while looking out of the open passenger window of a silver car before she vanished, according to The Sun.

The U.S. Embassy in Moscow offered their condolences to the family of Serou on their loss.

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WATCH: Missing UC Davis Graduate Catherine Serou Found Dead In Russia, Reports Say - From CBS Sacramento