WASHINGTON—Federal prosecutors on Wednesday charged two men they say were posing as federal agents, giving free apartments and other gifts to U.S. Secret Service agents, including one who worked on the first lady’s security detail. The two men—Arian Taherzadeh, 40, and Haider Ali, 36—were taken into custody as more than a dozen FBI agents charged into a luxury apartment building in Southeast Washington on Wednesday evening. Prosecutors allege Taherzadeh and Ali had falsely claimed to work for the Department of Homeland Security and work on a special task force investigating gang and violence connected to the Jan. 6 insurrection at the U.S. Capitol. They allege the two posed as law enforcement officers to integrate with actual federal agents. Taherzadeh is accused of providing Secret Service officers and agents with rent-free apartments—including a penthouse worth over $40,000 a year—along with iPhones, surveillance systems, a drone, flat screen television, a generator, gun …