Huangpu district prosecutors have charged a man who posed  as a university professor to swindle more than 10,000 yuan ($1,582) from seven people who eked out a living scavenging waste materials on the street, according to a press release issued Tuesday.

The university educated, unemployed 48-year-old suspect, surnamed Zhang, has been sent to prison four times on fraud charges, according to a press release from the Shanghai Huangpu District Prosecutor's Office.

On March 18, Zhang approached one of the seven victims, surnamed Ji, in a residential community.

Zhang introduced himself as a university professor and inquired whether Ji, a 47-year-old scavenger who lived in an underground garage, wanted to buy a large number of used books from him, prosecutors said. Ji accepted.

The next day, Zhang led Ji to the library at Tongji University in Putuo district. Zhang said that the university planned to renovate the library, at which time many books would be thrown out, according to the press release.

He said Ji could earn a lot of money by reselling the books instead.

First, however, Zhang asked Ji to give him some money to bribe the head of the library so he could secure the books, according to the press release. Ji gave 1,400 yuan to Zhang, who asked the scavenger to wait downstairs in a building while he made the deal. Zhang, however, never returned.

In May 2011, Zhang cheated another scavenger, surnamed Zhu, out of 2,000 yuan with the same scam, the prosecutor's office said.

Police arrested Zhang in May. By then, he had swindled seven recyclers living at the bottom of society out of more than 10,000 yuan.

The police said Zhang's familiarity with the city's universities and his sound promise allowed him to cheat his less-educated victims, according to the press release.