A researcher has been accused of stealing trade secrets from a US university laboratory, the second such case in as many months.

Yin Qingqiang was arrested while trying to pass through a security checkpoint at an airport on his way home to his native China with more than 100 glass vials and containers of materials he allegedly stole from a lab at Cornell University, where a potentially valuable new enzyme was being developed.

He has been charged with conspiring to defraud the US government.

Mr Yin worked as a postdoctoral research associate at Cornell until the university sacked him in July. He had been working on a project to develop an enzyme known as phytase, which researchers say will reduce polluting phosphorous in animal waste. The research was being paid for with a government grant.

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Prosecutors said they had found a letter in which Mr Yin sought a research job in China in exchange for providing materials that could have been used to copy phytase.

The incident is similar to a case in which two Harvard Medical School scientists were accused of economic espionage for allegedly stealing genes discovered in a Harvard lab and sending them to a biotechnology company in Japan. The genes could help transplant recipients to fight organ rejection.

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Kayoko Kimbara and Jiangyu Zhu, who are Japanese and Chinese respectively, said they were only planning to continue their research. They were charged with theft of trade secrets, among other things. The Japanese company has returned the genes and related materials.

Both men had signed agreements giving the university ownership of any discoveries they made while working there.

There have been several other cases of academic espionage during the past year. The home of a former University of California eye researcher was raided by police in May. They found 20 vials of a substance used in stem-cell experiments in a university lab.

The researcher, Bin Han, had been fired days before. The university said the vials were worth $1 billion (?650 million). Investigators found that Mr Bin had a plane ticket to China. It was later learnt that it was a return ticket, casting doubt on whether he was planning to steal the materials or was keeping them at home to save a trip to the lab, as he contended.

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