New York State Attorney General Eric T. Schneiderman’s office is investigating whether a Yaphank residential community founded as a summer camp for German-Americans has violated federal housing discrimination laws.

Officials in Schneiderman’s office issued a subpoena to the German-American Settlement League requesting a range of housing practice documents and how they were developed and implemented, Schneiderman’s office said Tuesday.

League officials were given one month to respond to the request, the officials said.

The subpoena comes after a federal lawsuit was filed in October by a Yaphank couple claiming that discriminatory covenant restrictions in the community have prevented them from selling their home.

Philip Kneer and his wife, Patricia Flynn-Kneer, said in court papers filed in U.S. District Court in Central Islip that the bylaws of the league, which owns the land in Yaphank formerly known as Camp Siegfried, restrict homeownership to residents who are “primarily . . . of German extraction.”

The lawsuit says the league’s bylaws also required the Kneers to advertise the house through printed materials circulated only to league members.

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The suit asks a federal judge to award unspecified damages.

The Kneers’ attorney, Diane Houk of Manhattan, didn’t immediately return phone calls.

Phone calls placed to the league also weren’t returned Tuesday.

State officials said the subpoena was issued to determine whether the league has been illegally operating and violating the 1968 Fair Housing Act, a federal law outlawing racial discrimination in housing.

A portion of Exhibit D from a lawsuit filed by Philip Kneer and his wife, Patricia Flynn-Kneer, against the German-American Settlement League, which they say restricts their ability to sell their house.

The Yaphank community, consisting of about 50 homes, was founded as a summer camp to support the German Nazi Party several years before the outbreak of World War II. Some of the streets in the community were named for Adolf Hitler and other German leaders. The street names were changed after the war.

The suit says the Kneers, who bought their house in 1999, have tried unsuccessfully to sell it for six years.