The body of a U.S. citizen has been found in Russia on Saturday, four days after she went missing. On Saturday, police in Russia reveal a suspect has been and is reportedly cooperating with investigators.

Catherine Serou, a 34-year-old American who was studying at a university in Russia, disappeared on Tuesday in Nizhny Novgorod. The last text Serou sent was to her mother in Mississippi, sharing her concerns about a car ride.

“In a car with a stranger. I hope I’m not being abducted,” the text read.

Serou’s mother revealed her daughter was in a rush to get to a clinic after a payment she made did not go through. It is suspected that Serou could have got into a passing car that wasn’t the Uber she ordered for her trip.

“I think that when she saw that the person wasn’t driving to the clinic, but instead was driving into a forest, she panicked,” said Beccy Serou. “Her telephone last pinged off a cell tower in that forest.”

Police arrested a local man born in 1977 who had a criminal history. He is being investigated on murder and abduction charges, which carry a maximum sentence of 15 years.

Serou’s body was discovered on Saturday morning about an hour after the suspect was taken into police custody. Around 80 police officers and 20 volunteers came together to search for the missing student.

Before attending school in Russia, Serou served in the Marine Corps and earned a bachelor’s degree and a master’s degree at the University of California, Davis.

She planned on applying to law school in the U.S. to become an immigration lawyer after completing a master’s program at Lobachevsky University.

The U.S. Embassy in Moscow revealed it was “closely monitoring” the investigation and is giving “all appropriate assistance” to Serou’s family in America.

Russian Sukhoi jet fighters fly over Moscow -- Russia and US have both decided to leave the post-Cold War Open Skies Treaty
Russian Sukhoi jet fighters fly over Moscow -- Russia and US have both decided to leave the post-Cold War Open Skies Treaty AFP / Alexander NEMENOV