REPORT: The Boston Suspect Admits To It
However, he had not yet been read his Miranda rights when he admitted to the bombings, meaning that Tsarnaev's defense team will almost certainly challenge the evidence if it is brought in court.
The 19-year-old Tsarnaev was formally charged on Monday with one count of using and conspiring to use a weapon of mass destruction and one count of malicious destruction of property with an explosive device. Tsarnaev could face the death penalty.
According to the criminal complaint filed against Tsarnaev on Monday, the victim of the brothers' carjacking told investigators that one of the brothers told him he had been responsible for the bombings. The carjacking victim is considered a key witness in the case.
"Did you hear about the Boston explosion?" the carjacker asked his victim, according to the complaint. "I did that."
According to the complaint, the carjacker then removed a magazine from the gun, showed the victim that he had a bullet in it, and re-inserted the magazine.
"I am serious," he said.
Police sources told the Globe, meanwhile, that Tamerlan Tsarnaev threatened the victim when they carjacked his vehicle.
“We just killed a cop," he said, according to the report. We blew up the marathon. And now we’re going to New York. Don’t [expletive] with us.”
Tsarnaev reportedly told police on Tuesday that he and his brother acted alone and out of religious motivation.