Four policemen have been arrested in Bangkok in connection with the disappearance of a prominent Thai lawyer, who had been defending nine Muslim militants.

The four officers denied the charges of robbery and detention, and declined to post bail. They vowed to fight the case. Two of the detained men are senior officers, the other two are police corporals. The arrests came shortly after Prime Minister Thaksin Shinawatra said police were involved in the disappearance of Somchai Neelahphaijit. For weeks, the government has denied any police involvement in his disappearance. Mr. Somchai disappeared in Bangkok on March 12. The fate of the well-known lawyer and human rights activist remains unknown. Human rights groups say Mr. Somchai was abducted to silence him for criticizing the rough tactics used by the police and military against the Muslim population in the country's southern provinces. At the time of his disappearance, Mr. Somchai was defending four Thais accused of belonging to the regional terrorist network, Jemaah Islamiyah. He had accused police of beating and torturing his clients.

The 52-year-old lawyer also was defending five Muslims, accused of involvement in a January raid on an army depot in the south that killed four soldiers. The January raid was the beginning of the violence that has rocked the Muslim-dominated south, and claimed more than 60 lives. The government blames the violence on Muslim separatists, but analysts say it is a combination of separatists, rivalry between the police and military, and common criminals. Political analyst Chaiyachoke Chulisuriwong of Bangkok's Chulalongkorn University says the arrest of the four policemen is important. He doubts, however, that it will change the heavy-handed tactics the security forces have been accused of using to quell the violence in the south. "I'm concerned that what has been done, the wrong should be made right," he said. "That also will have an effect also on those police who are using this kind of system ... what I'm very concerned is the wrongdoers should be brought to the court."

The majority of Thais are Buddhist, but around five percent practice Islam. The bulk of the Muslim community lives in the southern provinces near the Malaysian border.