Watcharin Panurat yesterday dismissed reports arrest warrants would be issued for police generals and colonels. He said the only development in the case was that the lawyer was now believed to be dead.

Watcharin said DSI investigators agreed the case of Somchai's disappearance should now be treated as murder. But the agency had not gone as far as identifying suspects, he said.

Somchai's wife Angkhana appealed to the DSI to reveal whatever information it has and to keep her informed of future developments.

Angkhana believed an "improved political climate" would make it easier for people to come forward.

Speculation over the involvement of a senior police general in the death intensified after Army chief General Sonthi Boonyaratglin suggested one suspect was a key aide to deposed prime minister Thaksin Shinawatra.

Somchai's disappearance - and the failure of police to explain it - is frequently cited as one of the grievances against Bangkok in Thailand's deep South, where a majority of residents are Muslims of Malay ethnicity.

Before his disappearance, Somchai publicly accused police of torturing four of his clients in custody.