DUBAI, United Arab Emirates  For more than a year, prosecutors have been cracking down on the corruption and kickbacks that thrived during the boom years in this Persian Gulf city-state. Dozens of executives have been arrested and charged in a high-profile effort to show that fraud will no longer be tolerated. Investigators say their cases have uncovered $3.58 billion that was stolen or used as bribe money.

But alongside the con artists and crooks, a rising number of businesspeople have been sent to jail for going into debt. Bouncing a check is a criminal offense here. That fact has begun raising questions about the fairness of Dubai’s laws, especially among the foreigners who make up about 90 percent of the population.

Consider the tale of Ali Fariq, a 33-year-old Iraqi real estate agent now serving a three-year jail term. Mr. Fariq says his ordeal in the Dubai legal system began last year when he was kidnapped and beaten by a diplomat who blamed him for an investment deal gone sour.

The diplomat, an Iraqi named Birhan al-Yacoubi, then forced Mr. Fariq  and later, his brother  to sign checks totaling $600,000, he said. She did not want the money; she knew they did not have it. Instead, she drove the men to a police station, where she presented the freshly signed checks as evidence of fraud, court records show.