Fashion designer Khadija Shah was taken into custody on May 23 after she surrendered to the Lahore police following constant hunt.
Ms Shah, the daughter of former finance minister Salman Shah, was wanted by the police, who claimed she was one of the key instigators of the May 9 attacks on the Lahore Corps Commander House.
The famed fashion designer was nominated in an FIR registered with Sarwar Road police under terrorism and other charges. Top police officials confirmed that Ms Shah appeared at the Lahore CIA head office and has been shifted to an undisclosed location for interrogation.
The fashion designer, who is a vocal PTI supporter, had gone into hiding since police started carrying out raids for her arrest, a top official said.
He added that law enforcement agencies intensified raids at various locations to arrest her on Tuesday after the Punjab IG expressed displeasure over the failure of the police.