Human rights activists have expressed doubts over the confessions offered by the two Burmese men who allegedly killed British tourists David Miller and Hannah Witheridge.

Two Burmese men - who Thai police say have confessed to killing two British tourists - have been paraded on the beach where the backpackers were found dead. Officers say they have DNA matches from the suspects - who were handcuffed and wearing helmets as they were put on show before the media. 

The Thai police have been under pressure to solve the crime as Thai officials believe the negative publicity has badly affected Thailand’s crucial tourist industry. Human rights observers expressed skepticism of the process, in particular the confessions, which were taken without the two men having access to lawyers.

The police investigation has been flawed since the start, with the crime scene left open and walked across and disturbed by media and the public in the aftermath of the killings.

"The suspects have been kept without legal representation. We still don't have lawyers observing the process directly," Pornpen Khongkachonkiet, a human rights activist told Reuters.

"So we are suspicious about the judicial process in terms of these alleged confessions."

The Thai national police chief, Somyot Poompanmoung, has said the two men made no request for lawyers.

The Thai police staged a public re-construction of the murders on the beach where Miller and Witheridge were killed. Public re-constructions are not unusual in Thailand and are frequently used by the police to solve such crimes.

Somyot said the attacks were motivated by sexual jealousy, the Guardian reports.

“The suspects saw them kissing and were aroused, so they attacked and got rid of the man and proceeded to rape the female victim.”“The suspects admitted that they are the real culprits so we have brought both to do a reconstruction,” he added.

Burmese migrant workers in Thailand have previously been wrongly accused of crimes and outside observers are wary of the desire of the Thai police to wrap up the case quickly.

A third man has been held since Thursday in connection with the case. Deputy national police chief Jaktip Chaijinda told Reuters the Thai police are aiming to close the case soon.

"Today the case should be finished because we want to clear this case up as soon as possible so that our tourism industry can bounce back," Jaktip said.