A man rides a motorbike past the entrance gate of a Huajian Group shoe factory in Ganzhou, in southeastern China's Jiangxi province, on Tuesday. (Mark Schiefelbein/AP)

Two days after the State Department called for the release of three activists detained while investigating working conditions at factories that make shoes for Ivanka Trump, Chinese authorities appear not to be backing off the case.

Reports published Wednesday morning by the Communist Party-controlled press claimed the three men, Su Heng, Li Zhao and Hua Haifeng, are being investigated for selling commercial secrets to unnamed foreign organizations.

A detailed report in the Paper, a website controlled by the Shanghai city government, claimed the men took jobs at factories and then used “hidden camera watches” and other devices to gather information and send it abroad.

The account included a picture of evidence reportedly seized by police: two watches, some thumb drives, a battery and a cellphone. It also said the men had confessed. The men are in detention and have yet to be formally charged.

The use of the party-controlled press to build a public case against activists will renew concern about how China treats human rights campaigners and uses its courts. The back and forth between Beijing and Washington could also complicate U.S.-China ties under President Trump. 

The current standoff started when three activists were detained while preparing a report about working conditions at Huajian Group shoe factories for China Labor Watch, a New York-based nonprofit organization that aims to defend workers’ rights.

China Labor Watch’s founder, Li Qiang, told The Washington Post last month that CLW investigators have been questioned and stopped from traveling over the years, but never detained.

“This never happened before in my 17 years’ experience,” he said then. “The only reason we think this case is different is that this is Ivanka Trump’s factory.”

On Wednesday, he said he now worries the men could face serious charges.

If the Chinese government indeed pursues the case, it could stop others from conducting investigations that have helped hold multinational companies accountable, said William Nee, a researcher with Amnesty International in Hong Kong.

“It could be that the Chinese government is now signaling that they are no longer tolerating this sort of workers’ rights research,” he said.

“Since China doesn’t have an independent trade union, and domestic workers’ rights NGOs have been squeezed, it will be very hard for workers to fight for their rights and may leave corporations to violate them with impunity.”

While Chinese police routinely target rights campaigners, the Trump connection quickly turned the China Labor Watch case into international news, calling attention to working conditions in Chinese factories — and the Trump family’s business ties abroad.

On Monday, the State Department urged Chinese authorities to either let the activists go or afford them the right to fair trial. A spokesman stressed that labor activists have been instrumental in helping U.S. companies understand conditions in their supply chains.

A spokesman for China’s foreign ministry on Tuesday dismissed U.S. concerns, saying it was an internal matter. On Wednesday, Hua Chunying, a spokeswoman for the China’s Foreign Ministry, said she had no new information on the case. 

Calls to local police and the shoe manufacturer’s public-relations department went unanswered. 

Behind the scenes, Chinese authorities seem to be stepping up pressure by isolating the activists and threatening their families. 

Deng Guilian, wife of Hua Haifeng, said her husband was being held in a cell with about 20 inmates who had all been told not to talk to him. “It’s very crowded inside,” she said, “He sleeps near the toilet, which is very painful and uncomfortable.”

Local authorities are now trying to turn her against her husband, she said: “They said that I have to make a clean break, or I too could be charged.”

Deng called on Ivanka Trump to issue a statement calling for her husband’s release. “For her, it’s just a matter of a few words, but those few words would save the entire family,” she said.

“I beg her, on behalf of my family too, to be kind and let my husband to come home as soon as possible.”

Carol Morello reported from Washington; Luna Lin and Liu Yang and Congcong Zhang reported from Beijing.