U.S. officials discovered last December that federal agencies had fallen victim to a cyberespionage effort pulled off largely through a hack of SolarWinds software. Now, the extent of the breach by suspected Russian hackers is becoming clearer. Current and former officials tell The Associated Press that the hackers gained access to email accounts belonging to the head of the Department of Homeland Security. They also gained access to email accounts of the department’s cybersecurity staff members whose jobs included hunting threats from foreign countries. The revelations come as the Biden administration tries to keep a tight lid on the scope of the hack.