A serial killer who murdered six people and raped 10 women and two girls, including a 12-year-old, was executed today, according to China's top court.

Zhao Zhihong, 47, known as the 'smiling killer', was sentenced to death in Inner Mongolia in 2015 for crimes committed in the northern region between 1996 and 2005.

He strangled most of his victims with his hands but killed one with telephone wire and slashed another.

Zhao Zhihong, 47, known as the 'smiling killer', was sentenced to death in Inner Mongolia in 2015 for crimes committed in the northern region between 1996 and 2005. Above, Zhao pictured at a courtroom at the Hohhot Intermediate Peoples' Court in February 2015

Zhao was arrested in 2005 and confessed to a string of crimes, including the 1996 rape and choking to death of a woman in the toilet of a textile factory in Hohhot, Inner Mongolia's capital. An 18-year-old named Huugjilt (pictured above) had already been tried, convicted, sentenced and executed for that murder. The teenager was posthumously exonerated after his family fought for years to prove his innocence

'The nature of his crimes was particularly gruesome,' said the Supreme People's Court, which has the final word on executions.

Zhao had conducted 17 crimes consisting of intentional homicide, rape, robbery and larceny in multiple places in Inner Mongolia, the court said in a statement today.

His crimes were conducted using 'extremely brutal means' and 'caused serious social damage.' Zhao refused to meet his family before the execution, the court added.

Chinese journalists who met Zhao dubbed him the 'smiling killer' because of his seemingly unflappable demeanour.

Zhao had conducted 17 crimes consisting of intentional homicide, rape, robbery and larceny in multiple places in Inner Mongolia, the court said in a statement. Above, Zhao pictured in 2015

Huugjilt was posthumously exonerated after his family fought for years to prove his innocence. In February 2016, Chinese authorities punished 27 officials for the wrongful conviction and execution of Huugjilt, whose case was considered to be one of the most notorious cases of judicial injustice in the country

On December 31 2015, the Inner Mongolia Higher People's Court ruled that Huugjilt's mother Shang Aiyun and father Li Sanren will receive around two million yuan (£238,000) in compensation for their son's wrongful execution. Above, Shang pictured in 2015

Zhao was arrested in 2005 and confessed to a string of crimes, including the 1996 rape and choking to death of a woman in the toilet of a textile factory in Hohhot, Inner Mongolia's capital.

An 18-year-old named Huugjilt had already been tried, convicted, sentenced and executed for that murder. The teenager was posthumously exonerated in 2014 after his family fought for years to prove his innocence.

In February 2016, Chinese authorities punished 27 officials for the wrongful conviction and execution of Huugjilt, whose case was considered to be one of the most notorious cases of judicial injustice in the country.

Acquittals are extremely rare in China and it is even rarer for convictions to be overturned.

Zhao Zhihong's crimes were conducted with 'extremely brutal means' and 'caused serious social damage.' He refused to meet his family before the execution. Above, Zhao seen in 2015

On June 10, 1996, Huugjilt was given a death sentence - despite the apparent lack of evidence - and was executed on the same day. Above, Huugjilt's devastated parents Shang Aiyun and Li Sanren mourn their son in front of his grave in Hohhot in December 2014

On December 31 2015, the Inner Mongolia Higher People's Court ruled that Huugjilt's mother Shang Aiyun and father Li Sanren will receive around two million yuan (£238,000) in compensation for their son's wrongful execution. Above, Shang seen in December 2014

According to local reports, Huugjilt, who was worker at a textile factory, found the dead body of a woman in a public restroom after hearing a cry for help on April 9 in 1996.

He alerted the case to the police who later arrested him on suspicion of rape and murder. Officers reportedly tortured him Huugjilt interrogation.

On June 10, 1996, Huugjilt was given a death sentence - despite the apparent lack of evidence - and was executed on the same day.

On December 31 2015, the Inner Mongolia Higher People's Court ruled that Huugjilt's mother Shang Aiyun and father Li Sanren will receive around two million yuan (£238,000) in compensation for their son's wrongful execution.

In another twist in the case, the top court today annulled Zhao's conviction for that crime due to a lack of evidence, according to state broadcaster CCTV.

China enacted new provisions in 2010 that strengthened the evidence requirements for death sentences, and in 2015 reduced the number of capital crimes from 55 to 46.