Recent attacks in the world's most populous Muslim nation have been by individuals or small groups, with less deadly results and targeting local "infidels" instead of Westerners.
The change signals Indonesia's success in tamping down on its main underground terror networks, but also shows how radical groups still operating in the open remain potent breeding grounds where angry young men can turn into attackers.
Syarif felt bitter and abandoned after his parents divorced a decade ago, family members said. A fan of firebrand cleric Abu Bakar Bashir -- even ducking out of his own wedding to attend a sermon -- he became increasingly difficult to be around.
"I didn't see much of him in the last few years," said Abdul Ghafur, his 66-year-old father, who was shocked when a picture of the bomber's face appeared on television after the April 15 attack. "We'd argue about religion. He'd call me an infidel ... Finally, I just gave up."
Indonesia, a secular nation of 237 million, was thrust onto the front lines in the battle against terrorism when the al-Qaida-linked network Jemaah Islamiyah attacked two crowded nightclubs on Bali island in 2002, killing 202 people, most of them foreign tourists.
While the group abandoned such tactics soon after, members of a violent offshoot continued near-annual suicide bombings on glitzy hotels, restaurants and an embassy, though those attacks claimed far fewer lives.
The last occurred almost two years ago. Experts credited a security crackdown that resulted in hundreds of arrests and convictions.
But that also contributed to the emergence of solo "jihadis" and small cells of former convicts or young men who meet at religious study groups and are able to operate beneath the police radar.
The shift is also in part ideological, the Brussels-based International Crisis Group said in a new report "Indonesian Jihadism: Small Groups, Big Plans." Low-level, targeted attacks result in fewer unintended Muslim victims -- something militants in the Middle East have long advocated.
That's not to say Jemaah Islamiyah and other groups have lost their influence in Indonesia.
Although authorities believe they have dismantled Jemaah Islamiyah's militant structure, remaining members operate legally, hosting religious study sessions, translating Arabic texts and handing out vitriolic leaflets. Their main goal is creating an Islamic state. They are most critical of the security forces and moderate Muslim leaders for joining the anti-terrorism fight and often fall just short of advocating violence.
In the last six months, small cells with no known links to Jemaah Islamiyah or other large jihadi organizations have raided police stations and assassinated officers. Mail bombs have been sent to liberal Muslim activists and an anti-terror chief and now, for the first time in Indonesia, a suicide bomber has targeted a mosque.
Police say the plotters of a Good Friday church bombing outside of Jakarta, all in their 30s and university educated, appear to fit the same pattern.
All this poses new challenges to authorities, said Ansyaad Mbai, who heads the country's Anti-Terrorism Agency.
"The book bombs, Molotov cocktails left at police stations and religious sites, attacks on officers -- they might not be as deadly," he said, "but that doesn't make them less serious."
Police are still trying to understand what motivated Syarif, whose home at Cirebon in West Java was found to have materials for bombs and how-to books on assembling them.
"For the time being we suspect that Syarif acted alone on his own initiative as a suicide bomber," said national police spokesman Col. Boy Rafli Amar said, though authorities were questioning his younger brother.
The portrait of Syarif drawn by relatives, friends and neighbors is of a troublemaker quick to judge fellow Muslims. Even those who empathized with his radical views often found him unpleasant.
While attending rallies against members of the minority Ahmadi sect, he would scream and shred banners. He was known to ransack stores for selling liquor.
Andi Mulya, who heads a chapter of a hard-line Islamic group, said he first met Syarif when he threw a tantrum at a mosque, kicking men who were resting on the grounds.
"He later told me the mosque is not a place for people to sleep or be lazy," said Mulya. "I know he had point, but I didn't agree with the way he handled it."
Syarif's father, Ghafur, had some forewarning, but only understood it after the attack, when words once said by his estranged son came flooding back: "Father, I will make a big surprise for you and the whole family."
Authorities are trying to determine whether Syarif built his suicide belt or obtained it elsewhere. It was packed with nails, nuts and bolts, but was either not very powerful or failed to exploded properly. It did not kill any intended victims.
Still, the belt and bomb appeared similar to those used in earlier attacks.
"Nowadays it's not hard to find people who can make bombs, "terrorism analyst Noor Huda Ismail said, adding that Indonesian militants who went to Afghanistan in the 1980s and 90s brought home bomb-making skills later used during sectarian conflicts in the eastern Indonesian districts of Ambon and Poso.
Sidney Jones, a leading expert on Southeast Asia terror groups, cautioned that the weakening of al Qaida-linked networks in Indonesia does erase the threat to Westerners.
Several key members of Jemaah Islamiyah and other violent factions are on the run, she said, and continue to forge ties with militants elsewhere in Southeast Asia and in the Middle East.