Police have detained a local official in Guangdong province in connection with the sudden death of Long Liyuan on 23 December.
The official, Huang Guang, is suspected of adding a toxic plant to the stew at a restaurant where they were eating.
Mr Huang, an agriculture official in Bajia, took Mr Long, who ran a forestry company, to visit a piece of woodland on 23 December, said the statement.
Afterwards, the two went to a local restaurant to share a local delicacy, slow-boiled cat-meat stew. A friend of Mr Long’s was also present.
Mr Huang is alleged to have added the plant Gelsemium elegans to the cat-meat dish.
Local media say Mr Long was taken to hospital after feeling dizzy and sick, and later suffered a cardiac arrest.
However the other two diners survived.
Police initially detained the owner of the restaurant on suspicion of serving unsanitary food, AP news agency said.
However Mr Long’s family did not believe it was a simple case of food poisoning and pressed police to investigate further as well as offering a $16,000 reward for information, the agency said.