They were among 22 foreigners, aged between 16 and 60, arrested from April 3 until last Sunday, with most of the eight being women and only three having documents.
State Police Commissioner Datuk Hamza Taib said all the eight suspects have been remanded until April 17 to be investigated under Section 3(1) of Kidnapping Act 1961 and Section 4 of Firearms (Increased Penalties) Act 1971.
"Of the 22 suspects, eight have been further remanded in relation to the recent kidnapping while the rest have been referred to the Immigration Department for further action, including deportation.
"In addition, the eight suspects are being investigated under Section 3(1) of the Kidnapping Act 1961 which carries the death penalty or lifetime imprisonment with whipping, upon conviction, and the Firearms (Increased Penalties) Act 1971.
"Earlier, the case was investigated under Section 365 of the Penal Code (for kidnapping or abducting with intent secretly and wrongfully to confine a person), which carries a maximum jail of seven years and fine, on conviction, and the FIPA 1971," he said, adding changing the provision for investigation showed that the abduction incident is a serious offence.
Hamza said this in a press conference at the Sabah police headquarters in Kepayan, here, Wednesday.
To a question, he said the parents of Marcy Dayawan @ Mimi, who was the Filipina resort worker kidnapped by the gunmen, were not among the eight suspects.
"What we know is that the two kidnap victims are safe in the neighbouring country and we are always in contact with the Philippines and Chinese embassies to fully address this case.
"Our main concern is to save the kidnapping victims and we are also strengthening our cooperation with Eastern Sabah Security Command (Esscom) in resolving the case," he said.
While refusing to comment if there had been any ransom demand, Hamza admitted that more than one phone call has been made in regards to the case.
"I can only say 'yes' that more than one phone call has been made and as I have said earlier, we are always in communication with relevant parties.
"No need for me to explain further about this because the police are currently making serious efforts to save both victims which is our prime concern," he said, adding that giving out details could jeopardise their investigation.
On whether the kidnappers are Abu Sayyaf militants in the Philippines, Hamza said the police will not leave any stone unturned in the case as all aspects are being looked into.
So far, he said the families of the kidnapped Chinese tourist Gao Hua Yuan from Shanghai have yet to come here.
"If they (families of Gao) do want to come here, they will contact the China Embassy and we will fully accommodate them," he said.
In the 10.30pm incident on April 2, a group of seven armed gunmen intruded into the Singamata Adventures Reef and Resort, and abducted a 29-year-old China student-tourist, Gao and the Filipina resort worker Macy Dayawan, 40.
Esscom Director-General Datuk Mohammad bin Mentek was reported as saying that the kidnappers holding the Chinese tourist have made a phone call to her family in China.
However, he declined to comment on whether the kidnappers had begun ransom negotiations with the Chinese family.