Jagan, as the Kadapa MP is popularly known, reached Dilkusha Guest House, the CBI camp office, at 10.30 a.m. He was accompanied by Congress MP Sabbam Hari and Congress legislators Alla Nani and S. Krishna Rao.
Jagan was questioned by the CBI for over seven hours each Friday and Saturday.
A few minutes before Jagan reached the guest house, his auditor and another accused in the case Vijay Sai Reddy reached there with his lawyer.
The CBI is likely to question Jagan in the presence of Vijay Sai Reddy, who is on bail.
The agency will also grill industrialist Nimmagadda Prasad and bureaucrat K.V. Brahmananda Reddy, whose 10-day CBI custody is ending Sunday.
However, former minister Mopidevi Venkataramna, who was arrested four days ago, was Sunday rushed to a corporate hospital after he complained of uneasiness.
During the last two days, the CBI questioned Jagan, Venkataramna, Prasad and Brahmananda Reddy individually as well as together.
The agency is grilling Jagan as to how his wealth increased dramatically after his father Y.S. Rajasekhara Reddy became the chief minister in 2004. The 40-year-old last year declared that he owns assets of Rs.356 crore.
The CBI believes that Jagan conspired with his father to dole out favours to certain companies in return for the investments they made into his firms.
Jagan will appear in the CBI court Monday.