A civil rights organization is suing a D.C. landlord after he allegedly placed an ad for apartments in Southeast Washington that told prospective tenants not to apply if they intended to use housing vouchers.

"It's very difficult [to even obtain a housing voucher], and that's what makes this source of income discrimination so damaging," said Don Kahl, executive director of the Equal Rights Center, which filed the lawsuit last week in D.C. Superior Court. "The program has a time limit for how long you can find a place and use the voucher -- and if they don't use it in the time frame given, they lose it."

Kahl said the ERC's lawyers contacted the landlord Theophilus LLC after they saw the ad on Craigslist in December, and mailed him information on fair housing law. Kahl said they got a signed return receipt from him on the correspondence but no response or change to the advertisement.

"It's certainly clear to us that the actions of this particular landlord were willful and intentional," Kahl said.

No attorney was listed for Theophilus. A person who answered the phone listed for the business' address in an upscale residential Bowie neighborhood immediately hung up the phone when the company's owner was requested.

The ERC says the landlord violated the D.C. Human Rights Act and the U.S. Fair Housing Act. The complaint said Theophilus also included language in the ad that said only people who are "working" and "professionals" should apply for an apartment at the property in the Greenway neighborhood in Southeast Washington.

"By refusing to rent to individuals who intend to use Housing Choice Vouchers, as well as individuals who do not have income as 'working' or 'Professionals,' Theophilus is unlawfully discriminating against renters in the District of Columbia based on their source of income," the complaint said. "Further, by refusing to rent to individuals who cannot work, Theophilus is unlawfully discriminating against persons who are unable to work because of their disabilities."

The ERC is suing for monetary and punitive damages to be determined at a jury trial. It is also asking for reimbursement of attorneys' fees.