SEATTLE (AP) — The Seattle Office for Civil Rights has filed charges against 23 landlords after a series of sting operations revealed that they discriminated against people posed as prospective renters based on family status, disability and use of Section 8 rent vouchers.

The Seattle Times reports that the charges stem from nearly 100 tests conducted by the office across Seattle between September and December 2015.

The office says in a news release that two charges were related to family status, six were related to disability and 13 involved Section 8 vouchers. The civil rights office also filed charges related to national origin and marital status discrimination.

Testing conducted by the office last year resulted in 13 charges against landlords for discrimination based on race, national origin, sexual orientation and gender.