China's pharmaceutical regulator said Friday that investigations have found that staff at a vaccine producer were suspected of criminal offences for using inferior materials and employing trickery in the vaccine production.

Local drug administration authorities and police launched investigations into the manufacture of substandard rabies vaccines by two pharmaceutical firms in Jiangsu and Hebei provinces, said a statement from the State Food and Drug Administration (SFDA).

Employees at Jiangsu Ealong Biotech Co. were suspected of criminal activities, but no evidence of criminal behavior was found at Hebei Bioforwell Co., said the statement.

Wei Liang, a senior official of the administration's Drug Registration Department, was charged with "taking bribes amounting to less than 1 million yuan (US$146,500)," according to an insider with prosecutors.

He told the 21st Century Business Herald that the money involved in Wei's case was "no big deal" but would not reveal more details "at such a sensitive time."

The SFDA announced in December that a total of 215,800 units of rabies vaccines made by the two drug makers from July to October 2008 had quality problems and had ordered the two companies to halt production and sales.

The statement said employees at Ealong Biotech were found deliberately using substandard materials, failing to follow legal manufacturing procedures and employed trickery.

The statement did not reveal the number of Ealong staff in question nor did it identify any of the suspects or what the trickery was.

It said the substandard vaccines made by Hebei Bioforwell were caused by operational faults.

It said the SFDA had as yet received no reports of adverse events from people who had taken the vaccines.

Police in Jiangsu are still investigating against staff of Ealong, said the statement.

Ealong Biotech is the nation's fourth-largest rabies vaccine maker with a market share of 11 percent. It took orders from the Chinese government for 6.3 million doses of A/H1N1 flu vaccines in 2009, ranking third nationwide.

Hebei Bioforwell Co., which only produced rabies vaccines, had been shut down pending improvements to the manufacturing procedures. The company has said that all the faulty rabies vaccines had been used, but they had received no reports of adverse reactions.