A newly-appointed chief of a local police station in the Guangxi Zhuang Autonomous Region who was accused of sexually assaulting a 13-year-old schoolgirl has been released after nearly a month in detention due to a lack of evidence.

In a meeting held on Sunday, public security authorities in Guangxi vowed to throughly investigate the case. Police in Guilin, Guangxin, said Saturday that the chief, surnamed Lü, who led a local police station in Quanzhou county, remained suspended pending the results of an ongoing investigation, the Xinhua News Agency reported.

Web users accused local authorities of shielding the police officer, leading Guilin police to pledge Lü will be charged if there is evidence he committed the crime.

The victim was reportedly stopped by four people while on her way home from school, forced into a vehicle and taken to a hotel in Quanzhou on January 17.

The girl told police that she was threatened and told to say she was 16 before being forced to have sex with a man.

The people who kidnapped her told the girl the man she was forced to have sex with was a police officer, Xinhua said.

She was then taken to two different hotels over the next two nights and forced to have sex with two other men before being dropped off near her school.

She reported the incident to police in Quanzhou on January 20. 

Police detained five suspects including Lü, and reported the case to the city police bureau in Guilin.

Yanshan district's People's Procuratorate has laid formal charges against two suspects, another two suspects were not charged as they are under 16, said Xinhua's report, which did not provide details on what caused Lü to be considered a suspect.

The girl's parents told Xinhua that their daughter is very depressed. The father said the police still have not detained two of the known suspects who kidnapped the girl.

Guo Miao, lawyer with Beijing Shouxin Law Firm, told the Global Times that if investigation finds that Lü sexually assaulted the underage victim he could not defend himself by saying he didn't know the child was under 14.

The Criminal Law was amended in 2007 to include the crime of "soliciting sex from a minor," which carries a sentence not as  harsh as statutory rape. Those found guilty of sexual assault can be sentenced to death, while charges of "soliciting sex from a minor" under the age of 14 carries a maximum punishment of 15 years in prison.

Guo also said officers of the law who are convicted of committing crimes usually face heavier penalties.