The city Commission on Human Relations is investigating Chatham Village, alleging that the cooperative on Mount Washington "is engaging in housing practices that discriminate on the basis of race [African-American]," according to a commission letter sent to residents with a survey.

Yancy Miles, a compliance supervisor for the commission, said he could not discuss details but that initial investigations are not necessarily prompted by a complaint from a consumer.

The manager of Chatham Village would not comment. The village's attorney, Deborah Liotus, could not be reached yesterday.

Chatham Village is a planned housing community that was built on the British Garden City movement in 1932. The main campus has 197 units -- two-story, red brick houses -- and an apartment building across the street holds 19 units.

Current residents told the Post-Gazette last summer they have had few black neighbors. But when residents bought the cooperative in 1960, they adopted a nondiscriminatory policy in writing, said resident historian David Vater.

"I don't have any insight into what's going on," said Mr. Vater. "The letter is very vague."

He said he doesn't understand why the commission is investigating the village when residents can sell their memberships on the open market. He said if the commission has concerns about certain individuals, it should take the issue up with them.

Chatham Village management told the Post-Gazette last summer that individuals are free to sell their homes on the open market, but the housing committee has to approve the buyer. When residents do sell their properties, the new buyer also buys the membership, which means they agree to their part of the fees for upkeep of the entire village.

The survey the commission sent to residents asks for the name and race of the owner they purchased their homes from, the name of the agent and real estate firm that represented the previous owner and the agent and firm that represented them.

It asks what percentage of down payment they were required to make and what the purchase price was.

It asks whether current residents have heard anyone associated with the village or a real estate agent make remarks of racial preference or limitations. It asks whether they know any black residents and, if so, for their names and addresses.

It was not known how long the investigation may take.