A young couple believed to have buried an elderly woman alive after knocking her down last month while drunken driving have been placed in criminal detention.

"It's certain the woman was not dead when buried," a publicity officer from Yuyao public security bureau, who only gave his surname Zhou, 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," he said.

But police have not formed a definite conclusion on the case, according to Zhou.

"Preliminary judgment of the cause of death is brain injury by the impact from the car and asphyxia," he said.

Police in Yuyao, Zhejiang province, received a report from construction workers about a car without license plates abandoned in a remote construction site on May 1. Officers found cracks on the windshield of the car.

Police received another report the next day from the same people that a body was buried in the mud nearby. They later found the corpse of an elderly woman 300 meters from where the car had been discarded.

Judging from the windshield and a bloodstain on the backseat of the car, as well as marks on the body, the police believe the woman might have been buried after being hit by the car on the morning of April 30.

"A witness said he heard someone crying and saw an elderly woman lying on the ground near a Santana. A man and a woman got out and put the elderly woman in the car, saying they would send her to hospital," said a policeman surnamed Song, from the criminal investigation brigade of the Yuyao public security bureau, who is handling the case.

The woman, surnamed Fang, was a 68-year-old native of Anhui province.

The young man and woman, both 25, were captured in Liupanshui city of Guizhou province on May 9.

Police believe the couple had been in a karaoke bar all night before the accident.

They believe the couple worried about criminal liability because of drunken driving and causing the accident, and may have found the elderly woman was no longer groaning and breathing on their way to hospital, said Song.

Shen Ning, a criminal lawyer from Shanghai Watson and Band Law Firm, said it could be considered intentional homicide if the woman was alive when buried.

"The approximate time of death and even the conditions at the site can be restored by forensic science," Shen said.

zhouwenting@chinadaily.com.cn