The 1-66 asset acquired by COPT.

WASHINGTON, DC-First Potomac Realty Trust revealed Monday morning it was selling most of its industrial portfolio to affiliate of Blackstone Real Estate Partners VII for $259 million. The portfolio, which it placed on the market at the beginning of the year when it announced it was realigning its investment strategy, will be sold via two separate contracts.

The portfolio consists of 24 industrial properties, pacing out to approximately 4.3 million square feet. Blackstone is buying approximately 4 million square feet, for $241.5 million.

The properties being acquired by Blackstone will be managed by IndCor Properties, its national industrial portfolio company.

Meanwhile, a 236,000-square foot complex in Haymarket, VA–I-66 Commerce Center–was sold to Corporate Office Properties Trust for $17.5 million. The property was occupied by Engineering Solutions through March 31, 2013, and was vacant at the time of the sale. will be looking more closely at this sale and the region’s industrial market in an update.