An expedition to find evidence of the mysterious wild man, Yeren, who some believe lives in the Shennongjia forests of Central China has ended in disappointment.

But a leading researcher said yesterday he is not downhearted and welcomes people and institutions from around the world to join in the search for the elusive creature.

"I cannot tell you where it is. But we are getting to the truth step by step," Wang Fangcheng, who is in charge of research into the Bigfoot-like creature at the Beijing Ecological Engineering Institution, said.

Last week, the institution organized an expedition to Shennongjia, a virgin forest in Hubei Province, to look for the mysterious wild man.

A team of scientists spent two days exploring the western part of the forest and spoke to local people who claim to have seen a large, hairy upright creature in the area.

"We didn't stay very long, however, because it was raining," Gao Dengyi, chairman of the institution, said.

Since 2005, the institution has set up three bases around Shennongjia and has found "some interesting and encouraging things", Wang said.

"We have found hair samples from an ape-like biped, footprints and feces. All of which show this is some new creature we do not know," Xiong Wei, head of the Shennongjia wild man museum, said.

"The footprints suggest the wild man stands about 2.6m, so he is even taller than Bao Xishun (the world's tallest man). And all the previous evidence we have found suggests it is not a monkey or ape," Wang said.

Xiong said more than 350 people - from school teachers to construction workers - have claimed to have seen the beast over the years.

"I can't say there is definitely a wild man in Shennongjia because we still have no real evidence. But it seems unlikely that all these people would lie," he said.