Police in Menghai county, Yunnan province, said on Tuesday that a female college student from Nanjing, Jiangsu province－who by Monday had been reported missing for 24 days－was killed by her boyfriend and two accomplices.

The student, Li Qianyue, was lured by two of her boyfriend's friends into a forest in the suburban county on July 9 before she was killed and buried at the site, according to the notice from the Menghai public security bureau on Tuesday.

Menghai police started to search for Li immediately on July 18 after receiving a message from Nanjing police, who had been informed by Li's father that she had gone missing. They became suspicious during the investigation and formed a task force to further probe the case.

They worked with Nanjing police to arrest the three suspects on Monday in Nanjing and unearthed Li's body in the forest in Menghai the same day.

Police said in a notice on Tuesday that the three suspects made the plan in Nanjing. The two friends of her boyfriend, surnamed Hong, then went to Menghai, about 2,700 kilometers away, to commit the crime.

The case is still under investigation, and the motive is unknown. It is not clear why Li traveled to Yunnan or how Hong and his two friends became suspects in her death.

Born in 1998, Li graduated from Jiangsu Vocational Institute of Commerce in Nanjing in June. She went to Kunming from Nanjing by plane on the morning of July 9 and arrived in Xishuangbanna Dai autonomous prefecture at 7 pm. The last known images of her were captured by surveillance cameras at an inspection station in Menghai later that evening.

Hong said he tried to get in touch with Li on July 10 but was unsuccessful. He said he watched surveillance videos in Maqun community in Nanjing, where he and Li lived together, before telling others he noticed she had left.

He said Li had not replied to his messages on social media since July 9.

Li Sheng reported his daughter's disappearance to Nanjing police on July 13.

After investigating, the police told him that his daughter had gone to Yunnan. He went to Menghai to look for her in late July but failed to find any information.

"I almost haven't had any sleep for days," he said. "My daughter was an optimistic and independent girl. She was our only child. Her mother has been bedridden since she went missing."

According to Li Sheng, his daughter brought Hong home to spend the Dragon Boat Festival with her family in Yangzhou, Jiangsu, in late June and said that they had first met each other on a subway.

In a video clip that went viral on social media, the father told a reporter earlier not to interview Hong, saying that he must be as worried as him and should not be disturbed.