The audit looked at subsidies handed out from July 2009 to November 2010 as part of the Senior Citizen Rent Increase Exemption program, which assists low-income elderly people in keeping up with rising rents.
City officials say they've already recouped $3.3 million and plan to collect the rest. Liu turned over his findings to District Attorney Cyrus R. Vance Jr., to investigate whether crimes were committed.
"There's no excuse for losing this much money - management lapse, willful fraud or otherwise," Liu said in a statement.
Tenants 62 or older and who live in rent-stabilized or rent-controlled apartments while making less than $29,000 a year are eligible for the SCRIE. The city then freezes the rent and allots their landlords a tax break to make up for the lost revenue.
Family members and landlords are supposed to notify the city within 30 days if the program's participants pass away or move.
Instead, according to The New York Daily News, family members and landlords of 3,801 tenants who were deceased, some for as long as a decade, continued to accept the tax credits.
The New York City Department of Finance, who runs SCRIE, admits they shouldn't have depended on family members and landlords to report the death of the program's participants.
From now on, the department says it will verify the pulse of the program's participants, checking their names against a master death list issued by the Social Security Administration.