Peter Humphrey Shanghai Trial
An internal court video shows British investigator Peter Humphrey at Shanghai No.1 Intermediate People's Court, on 8 August last year.Reuters

Yu Yingzeng, the American wife and business partner of British investigator Peter Humphrey, has been granted early release from a Chinese jail.

Both Yu and Humphrey were released early on 9 June. Yu was sentenced to two years and was due for release in July while Humphrey was given a two and a half years sentence for illegally obtaining personal information of Chinese citizens. Humphrey was to complete his jail term in January 2016.

The couple ran an investigative firm, ChinaWhys, which was hired by British pharmaceutical giant, GSK to investigate the source of a sex tape involving the company's boss in China. Shortly after, the multinational became embroiled in bribery allegations in the country.

An unidentified family friend told news agency Agence-France Press that Yu was released at the same time as Humphrey and that no other details are known, including the couple's exact whereabouts.

AFP said a spokesman for the US Consulate in Shanghai declined to comment. A spokesman for the British consulate in Shanghai however has confirmed that a British national has been released from custody and said it was providing assistance, according to the news agency.

It is understood that Humphrey has been in hospital for several weeks for medical tests for a potentially serious form of cancer. The

GSK was fined $490m (£318.55m) by a court in China after it was found guilty of bribing doctors and hospitals to have their products promoted. In addition, GSK's former head of China operations, Mark Reilly was handed a three year suspended prison sentence and was deported.

Other GSK executives were also given suspended jail sentences.