A stream of families walked, jogged, cycled, munched street food and enjoyed live music performances on Sunday morning. The festive scene took place within yards of the Starbucks that ISIS members attacked with suicide bombs and grenades on January 14.
The happy procession on Sunday was not specifically a response to the deadliest terror attack Jakarta has seen in six years, which killed at least 4 civilian bystanders and wounded at least 25 people.
For years every weekend, this teeming, steamy city closes vehicular traffic on several main boulevards as part of an initiative called "Car Free Day." But there was a spirit of defiance among many residents of the capital this weekend.
"This Sunday I'm quite happy, because look, everybody's here," said Rainier Daulay, an Indonesian hotel owner who took a break from exercising on his bicycle to smoke a cigarette.
"We don't care about terrorism."
He stood near a police traffic control booth that had been attacked by ISIS militants on Thursday. The battle-scarred structure was now decorated with the colors of the Indonesian flag as well as slogans that translated as "Brave Indonesia, Peaceful Indonesia."
In front of the Starbucks, still gutted and burned on the inside from the attack, men dressed in traditional costumes and skull and feather head-dresses danced with spears to the beat of a drum in a show of Indonesian patriotism.
Thursday's attack did not approach the scale of carnage caused by the 2002 al Qaeda-linked bombing on the Indonesian island of Bali, which killed more than 200 people.
In fact, counter terror experts here say ISIS only attracts a fringe minority of support in the world's most populous Muslim country.
And yet, law enforcement authorities warn ISIS represents a new generation of terrorists that could be more lethal than their al Qaeda predecessors.
"ISIS is more dangerous in the case of Indonesia...because they perceive Indonesia as not Dawla Islamiya, not an Islamic country," said Jakarta police chief Tito Karnavian in an interview with CNN.
Unlike al Qaeda, Karnavian says ISIS legitimizes the murder of fellow Muslims.
"I know some ISIS supporters personally," said Harits Abu Ulya, an expert on Islamist extremism and founder of the Community of Ideological Islamic Analysis.
"They are quick to declare that other people are infidels," he explained. "They accuse opponents of acting incorrectly to such an extreme level to justify killing them."
Friend of ISIS militant
Abu Ulya said for years he has been a close personal friend of Bahrun Naim, the 32-year-old who Indonesian authorities accuse of plotting the January 14 Jakarta attack.
"I consider him like a younger brother," he said with a smile.
Abu Ulya said he first met Bahrun Naim in their native city of Solo, where he led a local chapter of the Islamist movement Hizb-u-Tahrir.
"He was adventurous when he was in Hizb-u-Tahrir," Abu Ulya recalled. "Searching for answers including in matters of jihad."
A spokesperson for the group, Ismail Yunanto, confirmed to CNN that both men were members of the movement, which operates legally in Indonesia.
"Then in 2010 Bahrun Naim was expelled from Hizb-u-Tahrir," Yunanto said.
At that time, police arrested Bahrun Naim for possession of ammunition. He was sentenced to more than two years in prison.
Abu Ulya said that in prison, "Bahrun Naim became more militant ... he got closer to other jihadis."
Abu Ulya insisted that it wasn't until January 2015 that he knew Bahrun Naim had suddenly moved his family thousands of miles away to Syria. The radical had joined ISIS in Raqqa, the Syrian city that became the capital of the group's self-declared caliphate.
"His vision is to join, to unite all ISIS-supporting elements in southeast Asia: Indonesia, Malaysia and the Philippines," said Karnavian, the Jakarta police chief.
Communication from ISIS stronghold
Abu Ulya held up a Lenovo smartphone.
There, in a text messaging application called Telegram that he said was favored by supporters of ISIS in Indonesia, was a long series of messages exchanged with someone identified as Syam BN.
Syam is an Indonesian transliteration for the Arabic name for the Levant region of the eastern Mediterranean, which includes Syria.
Abu Ulya said several months after Bahrun Naim reached Syria, he contacted him via Telegram.
One of the final messages he received from the militant was dated December 3, 2015. Translated from the Bahasa Indonesian language it said "sorry sorry I was influenced by the boys." The message ended with two smiley-faced emoticons.
An undated photo of Bahrun Naim posted on his Telegram profile shows him dressed in a leather jacket, leaning against a wall decorated with Arabic flyers, holding a Kalashnikov assault rifle and wearing a Middle Eastern kaffiyeh scarf. The architecture of the buildings behind him is similar to structures one would see in many Syrian and Iraqi towns.
Since ISIS announced the creation of a caliphate around Raqqa in 2014, the region has served as a magnet for jihadis from around the world.
One ISIS-recruiting video shows a small group of men walking along a lake carrying weapons and an ISIS flag.
"We are your brothers from Indonesia who have come to join the Islamic state," says a man identified as Abu Muhammad al Indonesi. Speaking in Bahasa Indonesia, he urges fellow Muslims in Indonesia to drop familial and professional obligations to emigrate to Syria.
In a separate video, Indonesians demonstrate how they celebrate Eid al Adha, or the Feast of the Sacrifice, in Raqqa. And they repeat the appeal for Indonesians to make the pilgrimage to the ISIS stronghold.
Communicating via Telegram, Abu Ulya said he learned that Bahrun Naim took two wives and two children with him to Syria.
In fact, at Bahrun Naim's request, Abu Ulya said he informed the parents of the second wife that their daughter had gone to Syria.
"The parents are so sad losing her," he said.
In November, Abu Ulya learned that Bahrun Naim had been injured in Syria.
"He told me he was experimenting with chemicals and there was an accident," Abu Ulya said.
"Because of the accident, in his own words he became an 'office boy.'"
Around 14 weeks ago, someone identified as Bahrun Naim began posting blogs on a Google-plus account.
The articles include hand-drawn instructions on how to make an explosive belt, as well as lessons on making remote-controlled bombs and detonators.
Abu Ulya described Bahrun Naim as an "urban guerilla." He disputed the Indonesian government's claims, however, that his "little brother" was the leader of the ISIS movement in Indonesia, arguing that the 32-year old was too young to hold such a position.
However, several scholars of Indonesia's radical Islamist movements agree that with his social media profile and his presence in Syria, Bahrun Naim has become an inspiring figure for other young would-be supporters of ISIS on the Indonesian archipelago.
"Many people respect him even though he's very young," said Al Chaidar, a lecturer at Malikussaleh University in Indonesia's Aceh region.
"We can see the new role of a new generation of the jihadi movement," Al Chaidar added.
Last December, Indonesian police ramped up security before Christmas after intercepting communications that ISIS was planning "a concert." They interpreted that to be a codeword for an attack.
Abu Ulya told CNN that in November 2015 he received a similar message from his old friend in Syria.
"He once told me that he wanted to make a concert," Abu Ulya said. "The date of the concert is not fixed yet, but he told me just to wait."
Abu Ulya said it was far too early to conclude that Bahrun Naim planned the January 14 terror attack.
The militant's younger brother Dahlan told Indonesian media last weekend not to jump to conclusions about his sibling's alleged role in the suicide bombing.
"Regarding those allegations against Bahrun, I think we should just let the law take its course," said Dahlan Naim.