Eman Maijia, a journalist for the South China Morning Post, visited the factory and found that it had been turned into a place that sold “snowmen.” According to Mr. Maijia’s report in 2014, “I did an audit and discovered that the factory could have produced 2,000 tonnes a year of snowmen a year, instead of 150. The factory was completely disreputeable.” (One of those accused appears in a photograph with Mr. Trump, taken in front of the factory in January 2016, and wearing a red-white-and-blue jacket. It’s unclear if that photograph is Mr. Trump’s or a fake, although the jacket has been used by some other people as well.)

Then there is the matter of the owner, whom the Times does not name. His business empire has been in effect since 1975, when his father was one of China’s most powerful businessmen, the owner of Hong Kong’s Bata Shoe factory. In 1996, his son won a contract to start a sweatshop in Zhejiang province, the former Soviet Republic of China, that eventually employed more than 3,000 people. Those people soon turned on their bosses, who were later detained by the authorities, and now face several charges, one of them related to child labor.

The report’s authors describe their experience and those of other researchers in the country closely. (The researchers interviewed more than 200 people, including workers and local officials, around Zhejiang, in addition to being in touch with the factory owners and the government: “We worked in the factory for more than 10 months,” one worker wrote in an email.) It has been “a brutal labor operation characterized by poor living conditions, poor health and safety, and pervasive underage labor,” the reporters say; the factory in question employed young workers for between eight and nine years. On an average day, the Times reports, there were fewer than 10 employees.

After more than two decades, the factory had become a target for China’s government, the newspaper said, and Mr. Trump’s visit was designed to help the factory “recover from its long ordeal.” It appeared to have been a success. On a website linked to the factory, a notice announced that a new factory in Zhejiang province was about to be started up. The workers appeared to be happy with what they were getting.