Three men investigating a factory which produces shoes for the Ivanka Trump brand, along with several other retailers, have either gone missing or been arrested, it has been reported.

Hua Haifeng, Li Zhao and Su Heng had been probing a factory in Jiangxi province run by Ganzhou Huajian International Shoe City Co. where investigators had reportedly seen the manufacture of and the production orders for Ivanka Trump, Nine West, Marc Fisher and Easy Spirit items.

Li Qiang, executive director of China Labor Watch, told the Associated Press he had not been able to contact the three men since the weekend.

Hua's wife, Deng Guilian, said that the police had called her on Tuesday (30 May) to say that her husband had been accused of illegal surveillance and that she would not be able to speak to him.

China Labor Watch was preparing a report on the factory to be published next month which alleged low pay, exploitation of a student intern programme and excessive overtime. Li said that they had wanted to investigate the factory "to improve the labour situation" but that now "it has become more political".

The group has previously published reports on factories making products for Walt Disney Co., Samsung and Apple Inc. but Li said that they had not experienced interference from China's police.

Marc Fisher told AP that they were unaware of the allegation and "will look into them immediately". IBTimes UK reached out to the Ivanka Trump brand for comment but did not recieve a reply by the time of publication.

Hua's wife told AP that she had not told their children that their father had been arrested but that when she told her young son that his father would soon return, her son said "Papa was taken away by a monster."

It's not the first time the Ivanka Trump brand has been accused of using Chinese facilities with sub-par worker conditions. A report in April said that one factory used by the label paid workers only $62 a week.