Vaudine England – Attacks by men in Muslim garb wielding staves inside Jakarta nightclubs and bars – and last week at City Hall – are unlikely to happen again, according to a senior policeman.

"If God's willing ... there will be no more such violent actions because I have talked with these people," new police chief inspector General Mulyono Sulaiman said. "I believe they understood my remarks."

In recent weeks, members of the Front to Defend Islam (FPI) have burst into restaurants and bars on Friday and Saturday nights. Typically, they have trashed furniture and intimidated patrons, including foreigners and prostitutes, sometimes beating them.

Theories have flourished as to what lies behind the attacks. In past months, bars or suspected brothels in towns such as Bogor and Puncak, on the outskirts of Jakarta, have been burned or destroyed in attacks by Muslim youths claiming to be crusading against sin and the purveyors of immorality.

But a month ago, an attack on JJs, a popular nightclub in Jakarta frequented by foreigners, raised concerns that the FPI's goal was to support growing nationalist fervour by blaming foreigners for a kind of spiritual pollution.

Yet a week after the JJs attack, karaoke bars and discos in the Blora neighbourhood were trashed. This is not an area particularly frequented by foreigners, and even when outsiders were hit, so too were their Indonesian dance partners, further confusing the issue.

A week later, 200 police stormed the Hotmen's Bar in central Jakarta, a seedier version of JJs where foreigners easily find prostitutes. During the raid they also found evidence of drug-taking, giving them justification for the raid. Since then, the FPI attacks appear to have died down, at least until last week, when the City Hall was pelted with stones and the gate pulled down.

If General Mulyono is correct in saying the attacks are over, some security sources suggest another theory may be worth considering. They say the violence may be a turf war between different branches of the security apparatus, carried out by hired gangs of thugs which, in some cases, carry a radical Islamic banner.

It is unlikely that firm proof will be found to prove any theory, but some analysts point to the struggle between the police and the military since the formal separation of the two this year. They say that, as in many countries, different loyalties within the various branches of armed forces control different segments of business or protection deals.

The implication is that once a new balance of power is reached at the top, more carefree partying can return to Jakarta.