Amichai's disappearance on Friday morning had triggered a massive search effort, culminating in the grim discovery that sent shockwaves through the community.
The two adult victims were evacuated to Hadassah-Ein Kerem Medical Center in Jerusalem while the teen was being treated at Shaare Zedek Medical Center in the capital.
A Jordanian national illegally residing in the United States on an expired nonimmigrant visa, was learning to make bombs, stockpiling weapons and referenced attacking people at Jewish events in Houston.
The terrorist, who was armed with a knife, was neutralized by Israeli security forces at the Qalandiya Crossing after failing to heed calls to halt, according to police.
An IDF spokesperson said that security personnel have been deployed to the area and a manhunt launched for the terrorist or terrorists responsible for the attack.