Prosecutors have been forced to drop charges against 16 people suspected of drug offenses after they discovered irregularities in the way the police employed an undercover informant, the Justice Ministry said on Monday. Neither the ministry nor the police would publicly detail what the problems were, although one police source indicated that within the Central Unit of the Central District, which carried out the investigation, a number of irregularities existed. "There was a lack of synchronization in the unit and with the prosecutor's office. There was also a problem with documentation and the registering of reports in an orderly way," the source said. However, he was unable to confirm reports that the informant made money from selling drugs while he was acting for the police. Based on the agent's information, the police arrested the 16 suspects in November in an operation code-named "Calculated Risk." However, once the irregularities were discovered, Police Insp.-Gen. Moshe Karadi set up an investigation team, which handed in its recommendations earlier this week. It proposed that four policemen should be brought before disciplinary hearings for the misuse of an undercover informant and that warnings should be placed in the files of the other officers involved in the case. In addition, Karadi, who has accepted the recommendations, ordered the formation of a committee to consider transferring some of those who worked on the probe. The investigation team also proposed that the detectives in central units re-evaluate how they use undercover informants, and from now on, a senior officer from the Investigation and Intelligence Branch will have to supervise the use of such informants in co-operation with the Prosecutor's Office. Despite the irregularities that were discovered, the police source doesn't believe the affair will have consequences on other cases where informants were used. "It was a specific operation. It's not that all the agents in Israel are used in an incorrect way," the source said.