Sayfullo Saipov, a 29-year-old "radicalised" Uzbek man, was behind the wheel of the truck which killed eight people in Manhattan on October 31.
But the revelation about his country of origin led social media users to question why US President Donald Trump hadn't included Uzbekistan on his travel ban list.
The attack is the fourth major fatal incident within a year involving an alleged perpetrator with links to the Central Asian country, after attacks in Stockholm, Istanbul and St Petersburg.
In this courtroom drawing, defendant Sayfullo Saipov, right, addresses the court during his arraignment on federal terrorism charges, Wednesday, November 1.
Officials claim Saipov - who was shot by police but survived - planned his attack for up to a year in advance following instructions from Islamic State. His motives for taking up with the jihadist group are unclear.
New York Governor Andrew Cuomo avoided talking about the suspect's country of origin, saying he was "radicalised domestically" only after entering the US, "when he started to become informed about ISIS and radical Islamic tactics”.
Saipov first started planning an attack a year ago, before settling on the idea to use a truck to kill as many people as possible during Halloween celebrations just two months ago, according to a federal terrorism complaint.
"Saipov requested to display ISIS's flag in his hospital room and stated that he felt good about what he had done," a charging document revealed.
Authorities also announced they had found a second Uzbek man they'd been seeking in relation to their investigation, 32-year-old Mukhammadzoir Kadirov.
Sayfull Saipov has been charged with a terrorism charge related to the New York terror incident. (AAP)
Saipov is not the first Uzbek national to be linked to an act of terrorism. The International Crisis Group estimated that between 2000 and 4000 militants from Central Asia may have signed up under the banner of Islamic State.
The group says that the largest single group of IS supporters from Central Asian countries were either Uzbek nationals or ethnic Uzbeks from neighbouring states.
In January, Uzbekistan-born Abdulkadir Masharipov confessed to gunning down 39 people at the Reina nightclub in Istanbul on New Year's Eve. He will face trial in December.
In April, the suspect behind the fatal St Petersburg metro bombing was named as 22-year-old Akbarjon Djalilov; believed to be a Russian citizen born to an Uzbek family in Kyrgyzstan. The bombing left 15 people dead, including Djalilov.
And later that month, another Uzbek man, Rakhmat Akilov, was arrested after driving a truck into a crowd in Stockholm, killing four people. He was a rejected asylum seeker who had allegedly joined IS before the attack. Akilov admitted carrying out the attack at a pre-trial hearing.
In 2015, a group of Uzbek men and another man from neighbouring Kazakhstan were arrested in the US over allegations they were plotting to provide support for Islamic State.
All of the men had been living in Brooklyn, the borough that neighbours Manhattan where the Halloween truck attack took place. This month, 27-year-old Abdurasul Hasanovich Juraboev was sentenced to 15 years in a US prison over the matter.
Juraboev had posted online in August 2014 offering to kill then-President Barack Obama or bomb New York's beach resort Coney Island if ordered to do so by the IS group.
He was arrested in Brooklyn in February 2015 after buying a plane ticket to Turkey, from where prosecutors said he planned to join up with jihadists. US prosecutors plan to deport him to Uzbekistan upon completion of his sentence.
Central Asia expert Erica Marat claimed in an interview with Newsweek on Wednesday that radicalised Uzbeks were looking for “ways to belong” in a society where they struggled to assimilate.
“Patterns of radicalisation for Uzbeks are somewhat similar to that of migrants from other countries; an inability to fit into the society where they live, an inability to live the American dream. So they are looking for ways to belong and extremist narratives seem to be the most attractive,” she said.
"Uzbekistan is ready to use all forces and resources to help in the investigation of this act of terror," President Shavkat Mirziyoyev said.
"We condemn any forms and manifestations of extremism and terrorism," he said. "This merciless and very cruel crime cannot have any justification."
Uzbekistan is a majority-Muslim nation that for most of the last 200 years was a part of Russia and then the Soviet Union.
Bordering volatile Afghanistan, it is plagued with poverty, corruption and a highly controlling political regime – an environment which experts believe provides a motive for young men to head off to fight for IS.
The land Uzbekistan occupies was previously considered the heart of the ancient Silk Road trade route that connected China, the Middle East and Rome.
In 1991, Uzbekistan gained independence and the country has only had two presidents since; dictator Islam Karimov - until his death in September 2016, and the current, President Shavkat Mirziyoyev.
Under Mr Karimov, Uzbekistan boasted steady economic growth on exports including cotton. The Uzbekistan government also clamped down on militant Islam following the fall of the Soviet Union.
But the political system and country’s human rights record has since come under fire for its tight control on citizens and punishment of opponents.
Human rights groups have criticised authorities for closely controlling the population, restricting freedoms of association, expression and religion.
In the late 1990s, militant Jihadist group the Islamic Movement of Uzbekistan (IMU) was established with an objective to overthrow Mr Karimov.
The leadership pledged allegiance to IS in 2015, a move which forced the Taliban, formed in neighbouring Afghanistan, to retaliate and virtually eliminate the group. The IMU is considered a terrorist group by the US.
The group have claimed fighters were involved in the 2014 Pakistan airport attack and a series of bombings in the Uzbek capital Tashkent in 1999 and 2004.
Human Rights Watch claims that since Mr Karimov’s death and the installation of Mr Mirziyoyev as president, the country has failed to make enough of an improvement on their human rights record.
The harsh environment has resulted in many young Uzbeks fleeing the country; some of who have travelled to Syria to become IS fighters.
International terrorism expert Lydia Khalil told SBS News that at least 2000 foreign fighters from Central Asia have joined the terror group.
“Uzbekistan has a long history of conflict, authoritarianism and repression - all of which contribute to terrorism and violent Islamist movements,” she said.
While the New York attacker’s motive had not been officially declared, Ms Khalil suggested that extremism might have been an attractive option to someone who struggled to fit into a repressive society.
“I suspect that Sayfullo Saipov has had a common experience of someone who was not able to fit into the repressive society of Uzbekistan and its limited opportunities but at the same time was also unable to fit into an open society like America,” she said.
The US partnership with Uzbekistan in the war on terror in recent years is also considered by experts to be a likely motive for radicalised Uzbeks targeting Westerners.
The US claims to have worked closely with Uzbekistan in fighting illegal narcotics, people trafficking, terrorism and extremism. The US Department of State website says that Uzbekistan is important to the country’s interests in “ensuring stability, prosperity, and security in the broader Central Asian region”.
Between 2001 and 2005, the US also operated an airbase in the country and Uzbekistan’s location has been used to help to transport military equipment into Afghanistan.
“Uzbekistan is a key partner supporting international efforts in Afghanistan, primarily through the provision of electricity, development of rail infrastructure connecting Afghanistan and Uzbekistan, and support to the Northern Distribution Network logistics system serving North Atlantic Treaty Organization troops in Afghanistan.”
Ms Khalil said the US-Uzbek partnership could be a potential motive for the New York attack suspect.
“If he [Saipov] had any opposition to the Uzbek government, jihadism could be a way to exercise that opposition because of the US-Uzbek partnership in the war on terror.”
On Wednesday, Mr Trump confirmed Saipov had arrived in the US under the Diversity Visa Lottery Program, known colloquially as the green card lottery.
Mr Trump vowed to put an end to the 27-year-old program in response to the attack, a move which could quash US immigration hopes for millions of people worldwide. The lottery grants about 50,000 US permanent resident visas each year.
"I am starting the process of terminating the diversity lottery program," Mr Trump said angrily in the aftermath of the attack.
In 2015, more than 14 million people applied for the lottery. Of those, 49,377 won green cards, including 2,524 Uzbeks.
The US "must not" allow Islamic State jihadists to "return, or enter" the country after being defeated overseas, Mr Trump tweeted in the aftermath of the attack.
But Mr Trump’s stance on immigration has sparked questions over whether he is focussing on the right areas.
Experts claim his crackdown would not have prevented any of the deadly jihadist attacks inside the US since September 11, 2001.
The majority of attacks have been carried out by US-born or 'domestically radicalised' assailants. Most of the attackers’ families have links to countries not covered by Mr Trump’s travel bans – including Pakistan, Saudi Arabia and Afghanistan.
Mr Trump’s proposed list of 11 banned ‘high-risk’ countries includes citizens of Chad, Iran, Libya, North Korea, Somalia, Syria, Yemen as well as some Venezuelan Government officials and their families.
More than 80 percent of the population of Uzbekistan identifies as Muslim, according to Human Rights Watch, and the majority are Sunni.
The latest proposed ban was blocked by the federal court in mid-October but an appeal against the decision has been announced.