Achariya Ruangrathana, president of The Club to Assist Victims of Crimes took Mr Chuchart, 41, a construction worker, before reporters at the Crime Suppression Division (CSD) yesterday.
Mr Achariya said officers at the Sawaengha police station in Ang Thong arrested Mr Chuchart on a charge of illegal possession of 570 methamphetamine pills in 2006.
However, he insisted it was a case of mistaken identity as the real culprit was his brother, Somchai Sitthipolthep, 44, who looks like him.
Mr Chuchart was subsequently brought before the lower court, which acquitted him. The case then reached the Appeals Court, which upheld the lower court's ruling. Now prosecutors plan to take the case to the Supreme Court.
Mr Somchai, meanwhile, has not been charged with the drug possession. Mr Achariya said Mr Chuchart has been mistakenly prosecuted and does not want the prosecutors to appeal the case any more.
He was remanded in police detention for nine months during investigation.
Mr Achariya said Chamlong Changpradit and Somyot Saengthong, who were suspects in the drug case in 2006, had implicated Mr Chuchart.
The human rights advocate said the suspects mistakenly told police that Mr Chuchart was involved in the crime, rather than his brother Mr Somchai.
Mr Achariya said Mr Chuchart had denied the charge.
He said his client accused police of failure to check the brother’s identities before seeking his prosecution. Police pushed ahead to prosecute the brother they believed was the culprit and filed the case to the Criminal Court and the Appeals Court.
Mr Achariya said Mr Chuchart wants the case to end now as it would take about five years in the Supreme Court before a decision is reached.
"It's a waste of time," Mr Achariya said.
He said the defendant has received assistance from the Lawyers Council of Thailand. Mr Chuchart said he had been physically and emotionally tortured during detention.
He also said he has tried several times to contact his brother to confirm he is innocent.
Mr Achariya said he plans to file a petition with the Rights and Liberties Protection Department to ask prosecutors at Ang Thong provincial court to stop the case.