An affiliate of Blackstone Group, the New York private equity firm, will buy 23 industrial properties in Virginia, Maryland and the District as part of a sell-off of local property by Bethesda-based First Potomac Realty Trust.

With the sale, First Potomac makes another step in transitioning from an owner of large plots of industrial properties and suburban office parks to one more interested in office buildings in core employment areas.

In all, First Potomac will sell 4.3 million square feet for $259 million, it announced in a press release Monday. For $241.5 million an affiliate of Blackstone Real Estate Partners VII will buy the majority, about 4 million square feet that includes 16 assets totaling 2.6 million square feet in southern Virginia and seven others in Maryland and the District.

First Potomac will sell I-66 Commerce Center, in Haymarket, to Corporate Office Properties Trust, for $17.5 million.

Douglas J. Donatelli, chairman and chief executive of First Potomac, called the move in “the most critical step in our strategy of repositioning our portfolio to focus on high-quality office properties in the region.”

“We believe the sale, combined with the targeted portfolio management initiatives we have implemented, positions us well for continued growth in the greater Washington, D.C. office sector,” Donatelli said in the release.

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McLean-based Sotera Defense Solutions said Thursday that John Hillen will step down as the company’s chief executive and become vice chairman of the company’s advisory board.

The contractor’s board has begun searching for a new CEO, according to the announcement.

Hillen has run Sotera since 2008, including taking the company public in 2009 and selling it to a private-equity firm in 2011. (The company was previously known as Global Defense Technology & Systems.)

Though Hillen has spent many years in government contracting, he also served in government as assistant secretary of state for political-military affairs from 2005 to 2007 and was also an Army officer.

He declined to comment beyond the press release.

Sotera said in the interim it will be led by William Cave, who is executive vice president and general manager of the company’s defense and intelligence solutions unit, and Laurie Villano, executive vice president of Sotera’s cyber systems and solutions business.

A rendering of Towne Centre Laurel, the project replacing Laurel Mall. (Courtesy Greenberg Gibbons)

The developers who began tearing down Laurel Mall last summer announced Tuesday four prominent tenants for what will replace it, namely a Regal movie theater, Harris Teeter, Sports Authority and a new Burlington Coat Factory.

Greenberg Gibbons, lead developer of the project, announced that all four retailers had signed leases and that it was beginning preliminary work this month on turning the mall into the sort of open air, mixed-use town center that has grown in popularity as the allure of enclosed malls fades.

Towne Centre Laurel is slated to ultimately have 400,000 square feet of retail as well as 435 apartments. Construction on the $130 million project is scheduled to begin in earnest next month and the first new shops are scheduled to open in April of next year. The apartments won’t likely be done until the spring of 2016.

Workers install industrial-strength netting as a precautionary measure against falling limestone at the Washington National Cathedral following the 2011 earthquake. (Nikki Kahn - THE WASHINGTON POST) The Washington National Cathedral will receive $100,000 to fix damage remaining from the August 2011 earthquake after winning a social media contest put on by the National Trust for Historic Preservation and the American Express Foundation.

The contest, called Partners in Preservation, began April 24 and ran through May 10. To win points, owners and managers of historical properties encouraged supporters to post mentions, photos or videos of their properties on social media using the hash tag #PreserveDMV.

In all, the American Express Foundation will give $1 million to fund projects for historic properties in the Washington-area, based on the support the projects received during the contest and a panel of local preservation experts.

Every project in the contest will receive at least $5,000 and another dozen projects will receive more. Here’s a list of the grants the trust announced Monday:

Foodem has raised $600,000 from investors as the start-up continues to build a Web site where restaurants, hotels and other bulk food buyers can place their orders for fish, beef, vegetables and other items.

Foodem allows a bulk food buyer to compare prices from different distributors and place orders electronically. It then stores their shopping list and prices to streamline future orders and allow buyers to track costs.

Founder Kash Rehman said the company has recruited a raft of local food and restaurant supply vendors, including Metropolitan Meat, Seafood & Poultry, S. Freedman & Sons, FoodPro and Belair Produce, among others.

Bethesda-based Panacea Capital Advisors led the investment round, along with a slate of angel investors. The money will be used to continue developing the Web site and add to Foodem’s staff of five full-time employees, Rehman said.

The company was part of a business incubator program at Baltimore’s Emerging Technology Centers and secured $75,000 from the Maryland Technology Development Corp. last August.

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