Police in China arrested a young couple they say buried a 68-year-old woman alive because they believed they killed her in a drunk-driving crash.

The couple, drunk after leaving an all-night karaoke event at a bar, ran over the woman, surnamed Fang of Anhui province, in Zhejiang on April 30. Thinking she was dead, the driver and his girlfriend buried her at a construction site despite telling witnesses they were bringing her to the hospital, according to Xinhua news agency. Police believe the woman was alive when she was buried, the China Daily newspaper reported, though she was dead from suffocation when she was found.

It's certain the woman was not dead when buried, an official told China Daily on Wednesday. Legal medical experts detected particles identical to those in the surrounding soil in her lungs, which indicates she was still breathing.

Witnesses told police the couple loaded her into their car to take her to a hospital after the accident.

A witness said he heard someone crying and saw an elderly woman lying on the ground near (the car), a police officer told the China Daily. A man and a woman got out and put the elderly woman in the car, saying they would send her to hospital.

However, the couple was worried they would be arrested for drunk driving and instead buried her near the side of a road.

Construction workers reported an abandoned car without license plates at a site on May 1. The woman was found dead the next day by the workers, having suffocated.

The investigation continues.

Preliminary judgment of the cause of death is brain injury by the impact from the car and asphyxia, an officer told the China Daily.

The story gained international attention after it was posted to China's Weibo, a microblogging network similar to Twitter.