New Delhi, March 8 The CBI on Tuesday called the staff of Delhi Chief Minister Arvind Kejriwal's principal secretary Rajendra Kumar for questioning in connection with its probe into an alleged corruption case against him, an official said. "Two-three members of (Rajendra Kumar) Kumar's staff were called for questioning," a CBI official told IANS on condition of anonymity. The Central Bureau of Investigation (CBI) had earlier said the documents seized from the office of Kumar "prima facie reflect criminal conspiracy and criminal misconduct and abuse of official position by the accused persons". The CBI had conducted raid on Kumar's office on December 15 last year at the Delhi Secretariat. The issue came to light after Kejriwal on Tuesday tweeted and alleged that his staff was also called for questioning. "The CBI summons Delhi chief minister's staff 'informally' on phone without notice. Staff of other ministers called earlier like this." The CBI, however, denied that it called Kejriwal's staff for questioning.