Brookdale Investor’s Six L.P., the sixth real estate investment fund of The Brookdale Group, has acquired The Towers at Williams Square, a 1.4 million-sq.-ft. office complex comprised of four class-A buildings located in the Las Colinas submarket of Dallas.

The acquisition follows three other purchases made by Brookdale’s sixth fund over the last year, marking the most active 12-month period in Brookdale’s 17-year history in terms of both dollars invested and total square footage acquired. Following these recent acquisitions, the firm’s sixth fund, which closed in December 2009 with equity commitments of approximately $410 million, will have sufficient uncommitted capital to acquire an additional $600 million of Sunbelt office properties over the next several years.

Part of Brookdale’s ownership plan for Williams Square includes making almost $10 million of capital improvements to the complex, which was completed in 1985.

Williams Square features a 26-story office tower flanked by two 14-story towers and an adjacent five-story building, all of which are located on a 16-acre site fronting on Lake Carolyn in Las Colinas. Currently, the complex is 92.5 percent leased to 64 businesses, including Pioneer Natural Resources, Flowserve Corporation, Centerline AREA and La Cima Club. The complex is also home to “The Mustangs of Las Colinas,” one of the world’s largest equine sculptures featuring nine bronze mustangs arrayed across the project’s central plaza.

The Dallas office of HFF L.P represented the seller in the Williams Square transaction and also assisted Brookdale in arranging financing for the acquisition.

“The purchase of this iconic project in one of Dallas’ most dynamic submarkets anchors our sixth fund’s investment portfolio with an excellent asset that will continue to be professionally managed and leased by Cousins Properties,” said Fred Henritze, co-founder and president of Brookdale, in a statement.

Robert Turner, senior vice president and one of the Brookdale partners directing the sixth fund’s acquisitions efforts, added: “The Williams Square acquisition aligns perfectly with our current strategy of investing in class-A office properties in select high-growth Sunbelt office markets and submarkets.”