Former NSA employee Dalke, in a sting operation, sent a letter to an undercover FBI agent posing as a Russian operative, offering classified information. Dalke received a 21-year prison sentence for attempted espionage.
A former National Security Agency employee from Colorado has confessed to attempting to sell US classified documents to Russia, as per a plea deal reached on Monday.
After a U.S. naval engineer and his wife were arrested for trying to sell confidential data to another country, an army doctor and his wife were also arrested for trying to sell confidential information to Russia.
Argentina's former President Mauricio Macri testified in federal court over allegations of espionage against him for having spied on the relatives of the dead crew members of the submarine ship that sank four years ago.
The FBI has warned college students studying abroad that foreign intelligence officers are known to discreetly target and recruit young U.S. citizens with the purpose of gaining national secrets, Fox News reported.