The article doesn't say why the man did it, but I can tell you there have been plenty of nights I've been laying in my bed dreaming up undetectable ways to kill my neighbors dogs because they bark all night. I'd probably get caught if I used my rifle, but perhaps a poison hamburger. People who choose to own pets(especially those who live in the city) have a responsibility to keep their pets under control and reasonably quiet.
You are correct to be po'ed about dogs barking all night, I hope you can get help from the police or the city somehow. We all know how taking the law into your own hands can cost you dearly, and murdering someone's dog is not the answer. I once yelled at the top of my lungs "Shut your F%$#@in' dog up" out my window, and I heard a door open and did not have any further problems with an old dog in my 'hood. Good luck! There must be other people in your area that are as peeved as you are...