Seems that one of the cops shot in the "exchange of gunfire" the night that the 'splodey Tsarnevs got cornered and "Suspect #2" drove over "Suspect #1" (the elder brother), was likely shot by one of his brother officers.
Now, this is NOT an indictment of the police at the scene. Things got really, really sideways really fast, and they followed their training. Sadly, one of their fellow officers got hit by friendly fire. Luckily, he survived, but barely.
High energy, armed BOMB trowing suspects...in the dark.
Just shows how quickly things can go wrong.