The Islamic State claimed has claimed responsibility for the New York City terror attack that left eight people dead and Lower Manhattan on high alert this week. Eight people died when he drove a truck down a bike/pedestrian path in Manhattan on Halloween afternoon. "But when you say it, it makes it harder for DOJ to make that happen", tweeted Andrew C. McCarthy, a former assistant US attorney for the Southern District of NY.
He was allegedly in possession of three knives and thousands of IS propaganda images and dozens of videos that showed IS fighters killing prisoners.
Indeed, Pentagon officials appeared surprised at Trump's claims when pressed for evidence, offering a very content-light statement about how the USA always hits terrorists hard wherever they find them.
Saipov is the fourth Uzbek-linked man in less than a year blamed for deadly strikes overseas, following attacks in Istanbul, St Petersburg and Stockholm.
But an increasingly detailed picture is emerging of a suspect who only radicalized after moving to the United States, his ambitions thwarted, growing out a thick beard and reportedly developing a violent temper.
In the largely Muslim neighbourhood where Saipov lived with his wife and children for little over a year in the New Jersey town of Paterson, residents seethed with anger on Wednesday that he had besmirched their hard-working immigrant reputation.
He married an Uzbek immigrant, but ran up multiple traffic violations, lost jobs and an imam anxious that he increasingly misinterpreted Islam, the Times said. He is the only inmate among the 61 people on federal death row convicted for an act charged as terrorism.
Prosecutors said in court papers that Saipov asked to display the Islamic State group's flag in his hospital room and said "he felt good about what he had done". Prosecutors say he had meant to head all the way to the Brooklyn Bridge, killing many more people along the way.
President Donald Trump took to Twitter to say Saipov should get the death penalty.
He added: "There is also something appropriate about keeping him in the home of the terrible crime he committed". Trump said there was something "appropriate" about keeping Saipov where he committed the crime, and tweeted, "Should move fast".
Sen. Lindsay Graham, a Republican, on Thursday repeated his criticism of the Justice Department for charging Saipov in the courts rather than treating him as an enemy combatant. He had been shot in the abdomen by police, 24 hours after mowing down pedestrians and cyclists in a truck and colliding with a school bus.
"The defense is sure to raise this as unfair and raising questions about a jury being able to reach an impartial verdict", said James Acker, a professor at the School of Criminal Justice at the State University of NY in Albany who specializes in the death penalty.
"I'm not someone who believes in the death penalty", said Mayor Bill de Blasio, reflecting the views of many New Yorkers.
The West Side bike lane where the attack happened has since re-opened, allowing tourists and New Yorkers to enjoy the unseasonably warm weather, despite bouquets and an Argentinian football jersey in tribute to the victims. He killed 8 people, badly injured 12.