Sinopec technicians check pipeline facilities in Puyang, Henan province. [Photo/China Daily]

Three men were sentenced to life in prison for theft of refined oil worth 470 million yuan ($71 million), the largest case of theft in terms of value since the founding of the People's Republic of China in 1949.

The Beijing Second Intermediate People's Court sentenced Sun Weijing, Sun Lei and Sun Zhigang for the thefts from October 2009 to September 2012.

Sun Lei had an oil trade company in Beijing and is the brother of Sun Weijing.Sun Zhigang is Sun Weijing's nephew who had worked at China National Petroleum Co's Daqing Oil Field in Heilongjiang province.

Sun Weijing, former deputy chief economist of the Beijing Oil Products Co, a division of China Petroleum & Chemical Corp, the country's largest oil refiner, and his two relatives all appealed their convictions to a higher court.

The Beijing court found that the three men had built an oil collection facility on rented property in Beijing's Fangshan district in 2003, including underground storage tanks beneath two garages. They later tapped into a pipeline belonging to Sinopec's Beijing Yanshan Co and sold the oil, the court said.

Yanshan found that oil was missing in 2012 and reported the matter to the police, who later found the storage facility connected to the company's line by three illicit pipes.

Sun Weijing insisted he had not been involved in the theft.

The appeal is expected to be tried in open court soon.