She may be in shock yet.
She's probably going through a multitude of emotions.
The wife could have said a lot more than that, but that was the only part that was quoted. Newspapers do that a lot. That answer could have been in response to a direct question regarding the teen, and she took the high road. It's not unusual.
"...That's really amazing. I can't believe her attitude so soon after he was killed..."
The two of them may have been in the midst of a truly nasty divorce when her husband was killed. It would have been inappropriate for her to smile with glee, so she just took the high road.
This was the same phenomenon I theorized after the September 11, 2001 terrorist attacks. It seemed that nobody said, "Hey, I'm glad to see that two-timing, womanizing drunkard dead!", so they just took the insurance money, said a few nice words, and got on with their lives.
That said, the kid is an immature idiot who needs to be taught an extremely harsh lesson. He should get significantly more than a slap on the wrist.
~ Blue Jays ~