Police suspect an officer found dead in 2017 stole about ¥85.72 million ($774,000) in cash from a safe at a police station in the city of Hiroshima earlier that year, investigative sources said Thursday.

The police suspect the theft at Hiroshima Chuo Police Station on May 8, 2017, was an inside job. The cash, which was evidence in a fraud case, has still not been found.

The Hiroshima Prefectural Police have already decided to collect money from officers to cover the loss suffered by the fraud victims as a result of the theft, as they did not want to use taxpayer's money for that purpose.

The male officer in his 30s, who held the rank of inspector, worked in the community safety section of the police station until March 2017 and was involved in the fraud investigation.

He had returned tens of millions of yen borrowed from colleagues and others for gambling, but it was not known how he obtained the money.

The officer was found dead at his home in September 2017. He did not leave a suicide note and the cause of his death remains unknown, according to the sources.

The police have questioned around 600 people, including former and current officers of the police station. The safe was locked and its keys were in a drawer of the accounting section chief's desk when the cash was found missing.

It was also found that the section chief was supposed to take the keys home but had not done so at the time. The prefectural police plans to punish those who were senior officers of the police station at the time for failing to properly manage the safe.