Chang Si-ho, niece of Park's jailed friend Choi Soon-sil, has voluntarily submitted the tablet, spokesman Lee Kyu-chul said.
"On the tablet PC, there were a number of emails related to the establishment of Core Sports International in Germany and funding from Samsung, as well as a draft version of the president's speech for a meeting with senior presidential aides on Oct. 13, 2015," Lee said.
Investigators are looking into suspicions that the contract was signed in return for the state-run pension fund's backing of a major merger deal between Samsung subsidiaries in 2015. There have been allegations that the state fund was pressured by the presidential office to support the merger in return for favors Samsung gave to Choi.
Moon Hyung-pyo, chief of the National Pension Service, has been taken into detention over his involvement in the alleged irregularities.
"The person who submitted the tablet PC said it was used by Choi from July to November in 2015," Lee said.
After analyzing the email account, user name and other information, the probe team concluded that the gadget belongs to Choi, he added.
The ownership of another tablet PC found by a local media outlet, which ignited the mega scandal leading to Park's impeachment, has been continuously debated as Choi has said it does not belong to her.
"In case of the tablet PC (provided by Chang), we had no procedural problems in terms of obtaining it and thus we think there is no problem regarding its admissibility as evidence," Lee said. (Yonhap)