Never, ever call the police. And never speak to reporters.
Did they go too far? Maybe. It depends on what the truth is, and that may never be known. However, the burglar admitted being a burglar. And he was caught trespassing. The teens had every right to track him down to recover stolen property. If the thief then attacked them with a knife as they claim, they did the right thing by defending themselves.
In all cases I think it is right to give the benefit of the doubt to those who did not initiate force, fraud, or theft. The burglar committed theft, and doesn't deny it.
The cops do not wish to be seen as unnecessary. It is hard to justify living on stolen money, taken by coercion, if people can handle situations themselves. Yet, we can and they are unnecessary, and even promote crime by their very existence through the very mechanism displayed here. The "cooperate with the bad guys and just call the professionals" mantra. That is a recipe for defeatism.
It is a lesson the authorities hope we all learn. No thanks.
Please read my rejected column, along with an explanation, on my blog here: Accidents are not crimes