Indonesian police say they are closing in on Southeast Asia's most wanted terrorist, Noordin Mohammed Top, but a report released Friday says that the militant networks Noordin has established could launch attacks with or without him.

This is the latest picture, right, of Malaysian terror suspect Noordin Mohamad Top who allegedly has changed his appearance compared to the previous image, left (File photo)

Noordin Mohammed Top, a Malaysian fugitive, has escaped a four-year-long police hunt since he helped carry off the Bali nightclub bombings in 2002.

Noordin and members of the regional terror network Jemaah Islamiyah, or JI, have been blamed for a string of attacks in Indonesia that have killed dozens since the deadly 2002 bombings.

But a new report says that since 2003, Noordin has formed a new group of loyal militants from outside of Jemaah Islamiyah in order to launch his attacks.

Sidney Jones of the International Crisis group, who authored the report, explains how Noordin has used not just JI members, but a wide range of contacts from around Java and from such scenes of religion-inspired violence as Ambon and Poso.

"He's made use of people who have graduated from JI schools…or he has used contacts that he's made through the JI structure in East Java," said Jones. "But in addition to people who came out of JI, he's also just used personal contacts…so it's a question of taking one person who works for him and work through that person's contacts, who often were veterans of Ambon or Poso."

A week ago, Noordin narrowly evaded arrest when police raided a house in Wonosobo, in Central Java. Two key militants were killed, and another two arrested. Jones says that last week's raid likely inflicted a serious blow to Noordin's network, which was already weakened, but more attacks still can't be ruled out.

"I would think it would be much more difficult because he lacks the communication ability, he lacks the people, and its pretty clear that he lacks the money, to actually mount a major operation. But one of the characteristics of this man is that every single time…police arrested major figures in the team shortly before the operation took place, and it didn't deter him in the slightest," said Jones. "So he's got this ability to keep going."

Jones warns that even if Noordin himself were arrested, the network of jihadists he has established and trained could be used by other militants still at large.