SHIJIAZHUANG - A court in North China's Hebei province on Tuesday opened a trial for a man who allegedly added poison to frozen dumplings that sickened four Chinese and nine Japanese citizens.

The Shijiazhuang Intermediate People's Court began the hearing at 9 a.m. Tuesday. Journalists, as well as officials from the Japanese Embassy in Beijing, were present.

Defendant Lyu Yueting is being accused of the crime of deploying dangerous substances, which resulted in one serious injury and 12 other minor injuries, as well as significant losses of property, the Shijiazhuang Municipal People's Procuratorate said.

Lyu confessed to the crime in court, saying he felt sorry for the sickened people and did not expect his acts to cause such serious consequences.

Lyu previously worked at the Tianyang Food Plant based in Shijiazhuang, the provincial capital. He was dissatisfied with his salary and attempted to create an incident to attract the attention of managers in order to boost his salary, according to the procuratorate.

Between July and August 2007, Lyu entered the plant's refrigeration storehouse and attempted to inject insecticide into the dumplings with syringes, but failed.

He re-entered the refrigeration storehouse three times between October and December 2007 and injected insecticide into six to nine boxes of frozen dumplings,the procuratorate said.

The contaminated dumplings were sold to Japan and Hebei's city of Chengde. Nine Japanese citizens and four Chinese in Chengde fell sick after eating the food.

In January 2008, Japanese media reported that 10 people fell ill after consuming frozen meat dumplings produced by the plant.

The Tianyang Food Plant recalled its products and suspended its production after the incident.

Tests showed that the remaining dumplings from the same batch that was sent to Japan, as well as other batches produced by the company around the same time, were safe, according to Chinese quality inspectors.

The plant was investigated by both Chinese and Japanese authorities shortly after the incident, but no problems were found.

In March 2010, Lyu was detained by Chinese police. The 39-year-old man is a native of Jingxing county in Hebei and worked in the plant from 1993 to 2009.

After a three-hour trial, the court said a verdict will be announced on a later date.

According to Chinese law, the death penalty can be handed down to those found guilty of deploying dangerous substances if their actions cause serious injury, death or the loss of property.