A Chinese court has sentenced two men to death for their roles in the production of tainted milk that left six children dead and made nearly 300,000 sick. One of those sentenced at the Intermediate People's Court in Shijiazhuang, capital of northern Hebei Province, was Zhang Yujun. He was found guilty of making and selling over 600 tonnes of the powder between October 2007 and August 2008, worth around 6.8 million yuan (£720,000). Tian Wenhua, Sanlu dairy group's former board chairwoman and general manager, was sentenced to life for her role in peddling the milk powder which contained melamine. The industrial compound was used to cheat nutrition tests because its high nitrogen content mimics protein in some controls. Three other former Sanlu executives were given jail terms of between five years and 15 years, Xinhua news agency said. The company, which is now bankrupt, failed to report cases of Chinese children developing kidney stones and other complications from drinking their milk months before the scandal broke in September. The powder was bought by middlemen who added it to pooled, watered-down milk from farmers that was then sold on to Sanlu, which was partly owned by New Zealand's Fonterra group. The claims of official concealment and indifference have turned the milk powder case into a volatile political issue for the ruling Communist Party. And families hit by the scandal are demanding revenge, compensation and answers. Police detained two parents to stop them attending the trial of the dairy executives, one father and fellow activists said on Wednesday. Several parents who have been offered compensation under a government plan have said that the trial will not end their worries about their children's future. "What we want is not a verdict. We want the government to properly research the effects of melamine and tell us what to expect. Now melamine is still a blank," said Ma Hongbin, whose son Ma Tianxing had required an operation to remove kidney stones and ease complications. "I won't sign the compensation agreement until the government studies the long-term effects of melamine ... Compensation should be tied to that, not to some arbitrary guesswork."