The leader of Samsung Electronics' largest labor union and a senior union official are under investigation on suspicion of stealing the personal information of about 100,000 company employees to create a "union blacklist," information obtained by Yonhap News Agency showed Friday. The Hwaseong Dongtan Police Station referred Choi Seung-ho, head of the Samsung Electronics labor union, and the unidentified senior union official to the prosecution without detention on charges of violating the personal information protection law, according to the information. Choi and the union official are accused of compiling a blacklist, using illegally obtained personal information of employees that included their union membership. They are believed to have made such a list in and around March, when the union was preparing to launch a general strike over performance-based bonuses. The unidentified union official, who used to handle the company's internal systems, is suspected of unlawfully obtaining a file containing the names of more than 100,000 company employees and handing it over to the labor union.