HONOLULU -- Just a day after five city sweepers were indicted on a charge of theft in an overtime scam, KITV has learned that two of the indicted men were city supervisors, who nearly doubled their income with overtime, making almost $100,000 a year.

KITV broke the story of the investigation in April.

Investigators told KITV four of the five men have already confessed to the scheme in which one city supervisor approved bogus overtime for three employees in exchange for cash kickbacks.

The street sweepers work for the Department of Facilities Maintenance out of the city base yard on Sand Island.

Day-shift supervisor Manuel Castro was indicted Tuesday on charges of theft, bribery and tampering with a government document.

While Castro's base pay was about $50,000 last year, he nearly doubled his paycheck with overtime, taking home $96,000 and at least half his overtime was ill-gotten gains, law enforcement sources said.

Those close to the case said Castro admitted to getting 20 percent to 30 percent of his three employees' overtime kicked back to him in the form of cash payments of at least $80 a paycheck from each of them. That came out to at least $500 month in cash kickbacks.

The city has since started new overtime procedures, requiring higher-ups to verify extra work was actually completed before approving OT.

"When I came on board, we instituted these policies because we realized that overtime was rampant in our department," department director Jeoffrey Cuidiamat said in April when KITV first reported about the investigation.

The city said it has seen a 50 percent drop in overtime in the street sweeping section so far this year, compared to 2008 when the scam was under way.

City officials said the night-shift supervisor, Roman Thomas, rang up an average of four hours of overtime a day last year, raising his base pay of $50,000 to nearly $97,000. At least 50 percent of that overtime was for work he never performed, officials said.

Thomas was the only one of the five indicted street sweepers who did not confess to the scheme, according to people briefed about the investigation. He is still working for the city and will face an internal investigation.

The other supervisor, Castro, retired the day after he confessed and is now collecting his city pension. Castro's three underlings are on administrative leave with pay, pending the outcome of disciplinary proceedings, which could result in their being fired.

Investigators said the dollar loss to city taxpayers could be as much as $80,000 a year, but they are still adding everything up so the number could be higher.