Reston residents trying to block plans to turn a 166-acre golf course into a residential neighborhood said Thursday they have identified a previously unknown group of investors behind the potentially massive development, which has shaken those already living in one of the nation's oldest planned communities.

RN Golf Management LLC is the company that bought the land in 2005, land documents provided by Rescue Reston show. But RN Golf is part of a large group, RestonOaks Golf LLC, which, in turn, is owned by Wisconsin-based Northwestern Mutual Life Insurance Co. The insurance company is behind the push to develop the golf course, said Rescue Reston Executive Director John Pinkman.

"We feel it is important for our community to know who is calling the shots, who really owns the land," Pinkman said. "Through the efforts of Rescue Reston, we know Northwestern Mutual Life Insurance is behind all of this planning."

Development in Reston, one of the first posWorld War II planned communities, is tightly controlled. So when the owners of the golf course wrote in April to the Fairfax County Board of Zoning Appeals, asking the panel to clarify whether the tract was zoned for residential development, residents quickly mobilized against it.

Northwestern Mutual spokesman Mark Lucius acknowledged to The Washington Examiner that the company is part of a joint venture that owns the property, and said the group is "interested in fully clarifying the land use rights" of the golf course. However, "no specific future development plans" are in place, he said.

Members of Rescue Reston said residents were caught off guard by the development plans and have been trying to identify "the face of the opposition."

"It's absolutely staggering that no one came to community leaders [before appealing] and said, 'Hey, we're about to tear your town apart,' " Pinkman said.

The golf course owners requested a ruling from the zoning board after Cathy Belgin, the senior assistant to the zoning administrator, determined that the tract is classified as open space and is not eligible for development. The zoning board will consider the appeal on Oct. 24.

Calls to the course's owners and lawyer, Francis McDermott, were not returned.