NEW YORK -- The suspect in Tuesday's terrorist attack in lower Manhattan bragged to police about the deadly attack from his hospital bed, saying he would have continued mowing down bikers and pedestrians had he not crashed.

Sayfullo Habibullaevic Saipov, 29, told police he is pleased with his actions and is unapologetic for the attack, sources tell CBS News. One source said Saipov made "no bones" about the attack, which killed eight people and injured at least 12.

Investigators also discovered 10 to 15 pieces of paper with writing in Arabic praising the Islamic State of Iraq and Syria. One note said "ISIS will endure," sources say.

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Authorities also recovered knives at the scene.

Saipov was allegedly driving a Home Depot rental truck when he deliberately drove onto a bike lane along Manhattan's West Side Highway. He drove for several blocks before slamming into a school bus and coming to a stop. Police say he exited the vehicle and shouted "God is great" in Arabic before being shot by police and taken into custody.

The FBI has taken over the investigation into the attack.

Saipov is a native of Uzbekistan and entered the U.S. in 2010, according to a law enforcement official. He worked as a truck driver and has lived in Ohio, New Jersey and Tampa, Florida, since arriving in the U.S., BBC News reports.

Mirrakhmat Muminov, an Uzbek activist and blogger in Ohio, told BBC News he met Saipov shortly after he arrived in the country and was living in Ohio. Muminov said Saipov "had no knowledge of the Koran" when they met and was not well-educated. He said Saipov soon became depressed and resentful after he was unable to find a job as a truck driver. Muminov said Saipov was radicalized by information he saw on the internet.

"Because of his radical views he frequently used to argue with other Uzbeks and moved to Florida. From then onwards I lost contact with him," Muminov told BBC News.

Authorities say they believe Saipov acted alone and is not part of a wider conspiracy or plot.

"This was now, a classic case of a radicalization of a domestic jihadist who associated with ISIS, and this is their new playbook," New York Gov. Andrew Cuomo told "CBS This Morning" on Wednesday.