There was no active criminal investigation against the Tsarnaev brothers when the information was conveyed. The treaty regarding criminal investigations was not applicable to the Tsarnaevs. That was just basic exchange of intelligence, which was in the mutual interest of both countries.
Apples and oranges.
Ya think anyone buys that? ☺
Btw, you’re referring to the FBI et al, totally ignoring of warning from the Russians regarding those folks who bombed the Boston Marathon?
Begs the question, should this type of negligence not been subject to a criminal matter/investigation as well?