Adriana Hinojosa, 8th, Police Officer Kills North Texas student--motive?

Okay. I'm thoroughly confused about this whole article. Yesterday a student from the University of North Texas was shot by a police officer until he met death because he was at the wrong place at the wrong time. The student, Ryan McMillan, was seen in the school's parking lot holding an ax. Earlier that night, the officer had received several phone calls about there being a breakage of car windows in that same lot. Whether there is a correlation between Ryan and the car robberies, we don't know. What we do know is that Ryan was "wielding" the ax. The dictionary definition of "wielding" is "to use effectively." That being said it seems that Ryan was indeed swinging the ax at the officer. According to the article, Ryan was shot as he "advanced at the officer while holding the ax." This is just too vague for me. Advanced? Advanced could literally mean he was running, calmly walking, skipping, etc. And "holding the ax"? That makes it seem like he was passively holding the ax. This writer is inconsistent. What I am having trouble understanding is why police officers are equipped with tasers? I mean in a case like this it seems pretty logical to use a taser as opposed to a handgun thus robbing this 21 year old of his life when it obviously wasn't aggressive enough of an encounter. If it was, the journalist who wrote this article would not have such trouble deciding on what intensity level of adjectives to use. She is wavering between two different intensity levels of word choice thus making it seem she, too, is unsure. The article totals at about 10 sentences and the officer has not been able to prove anything he has said as true. I don't know about you, but this is already giving off a vibe of yet another innocent killing. Don't get me wrong, though. What that guy was doing in the middle of the school parking lot equipped with an ax in the middle of the night sure looks bad. But whatever it may have been, he didn't deserve to die. The officer obviously did not have enough of a motive considering he has not been able to give any major news source concrete evidence or really evidence of any kind.

http://www.nytimes.com/2015/12/14/us/texas-student-wielding-ax-is-shot-dead.html?ref=us

http://crimeblog.dallasnews.com/2015/12/unt-police-fatally-shoot-ax-wielding-man.html/