"They have confessed," said Chen Shiqu, deputy inspector with the criminal investigation bureau of China's Ministry of Public Security.
A Taiwanese official said Friday that the two parties will jointly investigate the case
before negotiating how the Taiwanese suspects will be prosecuted, according to Taiwan's Central News Agency.
The Taiwanese men and 32 suspects from mainland China were sent to Beijing from Kenya amid protests from Taiwan's government.
Beijing accuses them of being part of an elaborate scheme in which fraudsters posed as law enforcement officials to extort money from residents in mainland China, despite their being acquitted by a Kenyan court of those charges.
In one case, reported by China's state-run news agency Xinhua on Friday, one person was cheated out of $18.1 million. Other victims included migrant workers, teachers, students and elderly people, the report said. It added some of the victims committed suicide because of the money they lost.
The suspects come from two different fraud syndicates, according to Xinhua. Kenyan police arrested the first batch on November 29, 2014 and the second batch was apprehended on April 8.
"The suspects specifically targeted people on the Chinese mainland and their victims are from the mainland. Not to mention that many of the suspects are themselves from the mainland," Chen Shiqu said.
"They will thus be investigated, prosecuted and tried in accordance with mainland law."
However, Chen Wen-chi, Director General of Taiwan's Department of International and Cross-Strait Legal Affairs, seemed to contradict this, telling Taiwan's Central News Agency that "the issue of how to prosecute the suspects is being put on hold for later negotiations."
A Taiwanese official did not immediately respond to a request for comment on how the prosecution was being handled.
Kenya does not recognize Taiwan -- officially the Republic of China -- nor does it maintain diplomatic relations with Taipei.
Beijing regards Taiwan as part of its territory despite the island running its own separate political, economic, foreign policy and judicial system. China has praised Kenya for its decision to send the suspects to the mainland.
When the men were first sent to China, Taiwan called their citizens' deportation a "gross violation of basic human rights." A delegation from Taiwan is in Beijing to address the issue with Mainland officials.
Xinhua reports the Taiwan delegation were allowed to visit the suspects at the detention center where they're being held Thursday and that all were in good condition.
Last week, Chinese state-media published and broadcast interviews with two men reported to be among the 45 Taiwan citizens who appeared to confess to being part of the fraud syndicate
and described the scheme in detail. CNN cannot independently verify these reports, and it is unclear whether the men made their comments under duress.