If “Sign up to receive your slice of the civil war-era fortune left behind by the fleeing Nationalist army” sounds like a get-rich-quick scheme that’s too good to be true, that’s because it is.

A local court in southwestern China’s Yunnan province sentenced the two men, Shangguan Bin and Xu Jiahai, who masterminded the extensive con operation to 6 and 5.5 years in prison, respectively, state newspaper Legal Daily reported Thursday.

Before they were unmasked by authorities, Shangguan and Xu’s online pyramid scheme had fooled some 17,500 people from all over China to the tune of a combined 30 million yuan ($4.4 million).

The victims had signed up on the promise that they would receive their share of a fabled treasure dating back to the final days of the Chinese civil war in 1949. As the defeated Nationalist armies fled across the Taiwan Straits, they tasked several special agents with staying behind on the mainland to look after a large sum of money. Over time, the story goes, five of the agents transferred their treasure to the United Kingdom, where it was invested and converted into a massive fortune.

Bit by bit, they managed to return 6 quadrillion (a number with 15 zeroes) pounds ($7.5 quadrillion) back to China, and the agents supposedly wanted to share their literal good fortune with the country’s impoverished masses. According to Legal Daily, a website went online in November 2014 on which ordinary people could register to benefit from the soldiers’ generosity and receive a share of the bounty.

“Membership fees” for the website ranged from 900 to 9,900 yuan: Those who paid larger deposits would be given bigger cuts. The lowest-level members would receive 16 yuan per day, while those at the highest rung would get 220 yuan. However, these handouts were given in various forms of IOUs, not all of which could be turned into cash. If members signed up more people, they were told, the proportion of their handout that could be converted into actual money would become greater.

The pyramid scheme operated without too much trouble until, after about one year, the rate of new signups slowed, and Shangguan could no longer keep up with paying members. According to the report, he made up a rumor in September 2015 that the website had a virus, and that exchanging IOUs for money was not possible until the problem could be resolved.

Shangguan then set up a new website and told the scheme’s members to migrate there instead. But the process was messy, and members who had doubts about the operation’s credibility called for a meeting. It was during this time that authorities caught wind of the scheme.

The case was reportedly investigated by the prosecutor’s office of Qilin District in Qujing, a city in Yunnan. The office could not be reached for comment on Friday.

With contributions from Lin Qiqing.

(Header image: Moment Open/VCG)