Police in the city of Linfen in northern Shanxi province have identified the boy's aunt Zhang Huiying as a suspect because the boy's blood was found on her clothes, the official Xinhua News Agency said. Six days after the boy was attacked, Zhang killed herself by jumping into a well.
Initial reports said the boy, Gua Bin, was lured by an unidentified woman with a strange accent into a field on Aug. 24 where she used an unspecified tool to gouge out his eyes.
Xinhua did not cite a possible motive for the aunt to attack the boy. The police finding seemed to conflict with the family's initial comments on the boy's assailant, which cited him as saying that the woman spoke with an accent from outside the area and had hair that was dyed blonde.
One of the case investigators reached by phone, a police officer in Fenxi county surnamed Liu, referred only to the Xinhua report and refused to answer further questions, saying he was not authorized to speak to the media. Calls to the city and county's police bureaus' propaganda departments rang unanswered. Guo's mother's mobile phone also rang unanswered.
State media previously had raised the possibility that the boy's corneas were taken for sale because of a donor shortage in China, but police said the boy's eyeballs were found at the scene, and that the corneas hadn't been removed. At the time, though, Guo's father told The Associated Press the family had not actually seen the eyeballs.
The attack horrified the Chinese public, and added to outrage over violence against children in the wake of a scandal earlier in the year over a spate of cases of school teachers sexually abusing young girls.
Chinese Internet users expressed dismay as they circulated reports of the attack on the boy and links to footage showing him writhing in pain on a hospital trolley with bandages around his head, and his parents, both farmers, crying.
The Yanzhao Metropolis Daily quoted Guo's mother as saying the boy's account of the attack had varied from moment to moment.
"The child would say one thing at first and then another thing later. I asked him later, did she speak the way I do, and he said yes," the report quoted her as saying.
The report described the family as saying that they did not see the aunt's family frequently because they lived in different areas, though the boy was quoted as saying that he knew his aunt. Asked if the woman who grabbed him was his aunt, the boy said he did not know.