The discovery of hundreds of workers - some of them children - forced to work in illegal brickworks in China has caused a national scandal. The BBC's James Reynolds has been to Henan province to hear one family's struggle to find out if their missing son is among them.
Mr Zhang wants the authorities to help him find his son
"This is where he used to sleep - right here, " said Zhang Bairen, pointing to a bed in a small room next to his yard. The wooden slats of the bed are covered by sacks of rice.
"When he comes back, he will sleep here again," Mr Zhang added.
The old man is waiting for his 38-year-old son, Zhike, to come home.
Zhike has been missing for the last three years.
He is a migrant worker - one of millions of Chinese men who left their villages in search of work in factories or on building sites.
His parents say he used to call them regularly, using payphones because he did not have a mobile. But then, three years ago, his calls just stopped.
"He must have been kidnapped," said his mother, Wu Guoxiu. "If he was free, he would have called us or written to us. We've looked into everything - he must have been taken."
Zhike was his parents' favourite son. He enjoyed playing Chinese chequers, and they say he put off getting married so that he could work hard and send money to them.
His parents believe he was abducted and forced to work as a slave in illegal brick factories in the neighbouring Shanxi Province.
A week ago, they watched a local TV news programme in which a reporter managed to reunite a mother with her son, who been forced to work in a brick factory.
Chinese TV has broadcast pictures of recently-released slaves
The TV report shamed the police and the government into action.
Police officers raided underground brick factories and rescued hundreds of men and boys.
TV pictures showed the rescued workers looking confused and bedraggled. Their clothes were rags.
The Zhang family went to the local TV station to see if their son had been rescued, but the station said it had no information about anyone.
His father tried the local police, but was told to go back home and wait.
"If I can just get my son back, I'll let it be," Zhang Bairen said. "I don't have money or power. I don't count - I'm just a farmer."
I asked if the family had a photo of their missing son. They shook their heads and looked down. They are too poor to have any family photos.
But the neighbours had come round to listen to our conversation and they tried to help.
"Zhang Zhike looks just like his father," one man said confidently. "He also looks like his sister."
But this description is too vague to be of much use if the family decides to start searching for their lost son.
"Why don't you start searching?" I asked quietly.
Zhang Bairen did not answer. He cannot hear very well anymore. So his son-in-law, Li Yundong, replied instead.
"We want to look but we don't know where to start," he said. "We know the general area but we'd need help. And the local government certainly won't help."
The family is scared of what might happen to them if they start searching.
They, and many others in this region, believe that brick factory owners and local officials will work together to stop families from making a noise.
Still, some will go ahead and try anyway.
Many, at least, will have a photo of their missing relative that they can show around.
The family of Zhang Zhike does not even have that.