Boston bombings suspect Dzhokhar Tsarnaev left a note claiming responsibility for the attack, reports CBS News correspondent John Miller.
Sources tell Miller that Tsarnaev wrote the note in the boat he was hiding in as police pursued him, and as he bled from gunshot wounds sustained in an earlier shootout between police and his older brother.
The note, scrawled with a pen on the interior wall of the cabin, said the bombings were retribution for what the U.S. did to Muslims in Afghanistan and Iraq, and called the Boston victims collateral damage in the way Muslims have been in the U.S.-driven wars. When you attack one Muslim, you attack all Muslims, the note added.
Dzhokar said he didn't mourn older brother Tamerlan - the other suspect in the bombings - and said Tamerlan was a martyr in paradise by then - and that Dzhokar expected to join him there.
Miller's sources say the wall the note was written on was riddled with bullet holes from shots fired into the boat. The shots were fired after Dzhokhar came up through the tarp that was covering on the boat and a police officer watching that side of the boat thought Dzhokhar had another bomb.
The note, says Miller, will be a significant piece of evidence in any Dzhokar trial - it is clearly admissible, and paints the clearest picture authorities have of why the brothers did what the note says they did. There will be a big argument at trial over whether other things Dzhokar said before he was given his Miranda rights is admissible.
Investigators struggled with not having a claim of responsibility, Miller observes. It took days to learn the identity of the bombers, and there was no official claim of responsibility, which is unusual in these cases.
The suspects didn't plan to stop after the Boston bombings, authorities say. They intended to go to New York City and set off a device or devices in Times Square.
The brothers didn't have well-developed plans for New York, but they still had intent, Miller says. So as Dzhokhar lay in the boat, he wanted to leave a message behind clearly supporting what the note says he and his brother had just done.
For a plot as organized as the one was for Boston, it seems odd that -- with a choice of leaving behind a martyrdom video on a computer or a more formal claim of responsibility - the brothers had nothing prepared, Miller says. A larger terror organization ensures that such videos are made out of the country and are ready to launch after the attack.
It appears these guys cobbled their plot together themselves and didn't have the organizational skills to plan out their end game, which would have included putting together a formal claim of responsibility.
So in the end, Miller concludes, the boat note was a way for Dzhokhar to get on the record as publicly claiming responsibility for the bombings.