(AFP) Police said today there was no evidence to indicate Swiss environmental activist Bruno Manser, who has been missing in Malaysia for 18 months, is dead.

Despite suggestions by the Basel-based Bruno Manser Fund that he had died, a recent police investigation in Sarawak state on Borneo island had failed to establish this, said state police chief Mohamad Yusoff Jaafar.

There was no sign that he had died, been murdered or was lost in the area, Mohamad was quoted as saying by the official Bernama news agency.

"Nonetheless, the police are not closing the case and will continue our investigations should we receive reports from any parties on Manser," he said.

Manser ( photo, centre ), a staunch defender of the nomadic Penan tribe and the rainforest in Sarawak, returned to the state on May 23 last year and has not been heard from since May 25.

No trace

John Kunzli, secretary of the Bruno Manser Fund in Basel, said in August that two private search expeditions to Sarawak failed to find any trace of Manser.

"It is very difficult for us, his friends and families, his office and companions in the struggle, to believe he is still alive," Kunzli said.

The 47-year-old activist was planning to climb up Batu Lawi, a 2,000-meter sheer limestone pinnacle in Sarawak.

"It is possible that Bruno may have had an accident. Our worst fear is that he has fallen down the mountain in Batu Lawi, which is very difficult to climb but we have not found his body nor his belongings," Kunzli said.

He said Manser had fallen foul of the state government, which considered him a nuisance due to his work for the Penans.