China has revived a legal case against a detained New York Times researcher two months after dropping charges against him, his lawyer said.
Zhao Yan was arrested in September 2004 and was facing charges of leaking state secrets and fraud.
But the charges were dropped in March one month before a US visit by Chinese President Hu Jintao.
Lawyer Mo Shaoping said there was a new indictment against his client, but he did not know what the charges were.
"The prosecutors notified me last Friday that they had re-transferred the case to the Beijing Second Intermediate Court one or two days earlier," he told Reuters news agency.
He said prosecutors had told him they were "resuming criminal investigation and prosecution", but he said there was no legal basis for this under Chinese law.
"It is definitely a prolonged and illegal detention now," he said.
Mr Zhao, a Chinese national, had faced 10 years in jail after security officials alleged he told his employer, The New York Times, details of a power struggle between retired Communist Party leader Jiang Zemin and his successor, Mr Hu.
It was thought that Mr Zhao would be released within days of the prosecution withdrawing the case on 17 March, but he has remained in custody.
Mr Zhao has denied the charges against him. The New York Times newspaper also denies he has disclosed state secrets.