JAKARTA (THE JAKARTA POST/ASIA NEWS NETWORK) - The sword-wielding Indonesian man who attacked a congregation in Yogyakarta during Sunday (Feb 11) mass is believed to have acted alone, according to police.

At least four people were injured when the suspect, who police identified as 23-year-old Suliyono from Bayuwangi in East Java, stormed into the church wielding a one-metre-long sword and began attacking people indiscriminately.

He also decapitated a Virgin Mary statue with his sword and was later shot in the leg by police.

National Police spokesman Setyo Wasisto said on Tuesday (Feb 13) the police had not yet found if Suliyono had any links to extremist groups and had concluded that he was a lone-wolf terrorist.

He said the incident on Sunday conformed to a pattern of terrorist attacks that have taken place in countries across the world in recent years.

The police previously said that Suliyono was a radical Islamist who had wanted to fight with Islamic State in Iraq and Syria (ISIS) militants in Syria.

He added that Suliyono was radicalised when he joined several religious organisations as a school student in Sulawesi, but refused to disclose the names of the organisations, which may have influenced Suliyon with radical teachings.

Three days before the attack, Setyo said, Suliyono stayed in a prayer room in Yogyakarta and reportedly communicated with the man who takes care of the mushola. During his stay, Suliyono searched on the internet for the nearest church and where to find a weapon.

"He exchanged his mobile phone for the 1-metre-long sword (used in the attack)," said Setyo.

The police also found that Suliyono had applied for a passport two or three times in an attempt to travel to Syria, however immigration officials rejected all of his passport applications because of ID-related issues.

The police named Suliyono a terrorist suspect on Tuesday, where he was charged under three different laws on persecution, sharp-weapon ownership and terrorism.

Suliyono could face the death penalty as stipulated in the 2003 Terrorism Law, which is being revised and deliberated in the House of Representatives.

He was taken to Jakarta for further questioning on Wednesday.

The church attack followed two other religious-related incidents in the country. Two weeks earlier, a group of people disrupted a social care program at the St. Paulus Catholic church in Bantul, Yogyakarta, accusing the church of using the event to convert people to Christianity.

Earlier this month, a Buddhist monk from Caringin village, Tangerang regency, Banten, was forced by local residents to write a letter promising to stop his religious activities.

Former terrorist Ali Fauzi explained to The Jakarta Post that it was likely Suliyono had chosen Yogyakarta as his target because its population had diverse religious, ethic and sociocultural backgrounds. "It seemed he knew very well that attacking this region would trigger widespread societal conflict," said Ali.

Jakarta-based Institute for Policy Analysis of Conflict director Sidney Jones said on Tuesday that in some cases, extremists targeted churches because they were seen as trying to convert Muslims.

"Many violent extremist groups, including those linked to the Islamic State (ISIS) movement, are taught that Christians and Jews are the enemies of Islam," she said, citing the Bethel Church bombing in Surakarta, Central Java, in 2011, as an example.

However, Jones said, based on previous cases the police would continue to be the primary target for terrorists.