Islamabad: The chairman of Pakistan’s financial regulator was arrested Friday, accused of forging documents in a corruption case against Prime Minister Nawaz Sharif that has gripped the country.

Head of the Securities and Exchange Commission Zafar Hijazi was accused by investigators of doctoring the records of a sugar mill owned by the Sharif family.

Hijazi, who is seen as a trusted ally of Sharif, had appeared in court on Friday morning for a bail hearing and was arrested during the proceedings.

The arrest comes just over a week after the investigating team, tasked by the Supreme Court with probing the graft claims, said that documents naming Sharif’s daughter Maryam as a trustee for several of the family’s high-end London properties were also “falsified”.

Dated 2006, they were typed in Microsoft’s Calibri font, which was not released for commercial use until 2007, the joint investigation team (JIT) said, citing forensics experts.

The allegations are fuelling intense pressure on Sharif from opposition parties to resign. His main political rival, cricketer-turned-opposition leader Imran Khan, has called for him to be sent to the prison.

“The prime minister’s final destination is Adiala jail. Now I am not demanding his resignation, but imprisonment,” he told reporters on Thursday.

But Sharif has been defiant, insisting he has no reason to step down.

“This is not accountability. This is exploitation,” Sharif said while addressing supporters in the northern region of Dir Thursday.