"It is still being investigated to which groups the nine terrorist suspects belong," head of the police public relations division Insp.Gen. Boy Rafli Amar said at the police headquarters here on Monday.
Boy said the nine are still in the process of interrogation by police investigators.
"We could not yet take a conclusion whether they belong to the Santoso group," he said.
Santoto led a gang of Islamic terrorists creating security problem for a long time in Central Sulawesi before he was shot dead by police last year.
The nine suspects were piked up from separate places on Thursday and Friday last week.
They were IRH alias AAN, from the village of Dangi, sub-district of Parigi Utara, regency of Parigi Moutong, AJ alias Jufri alias Abay, from the sub-district of Palu Selatan, MD alias D alias Kelo, from sub-district of Palu Selatan - all arrested on Thursday.
The other six were nabbed on Friday including SMD alias SAM from Toli-toli, KIF from the city of Poso, SYN from the city of Poso, DWN alias ALI from the regency of Poso, IRS alias ICAN from the regency of Toli-Toli, and JEF from the regency of Lampung Selatan.
The suspects told their investigators that they planned to explode bombs at police and military headquarters in the regency of Toli-Toli.