The story starts out giving the most important and newsworthy information: what happened, when, and to who. The reporter also stated in the lead that it occurred after the students had been released which is good since that would be a pertinent question in many people's minds.
The reporter summarized the important events by simply answering the who, what, when, where, and why questions first before going more into detail and background information.
The way they ordered the information, by putting important story facts first and then going into background information, was very effective because you can skip reading the last bits of information and still get the story.
The only thing I wish the reporter would have done is reiterated earlier in the story that there were no students in the school. Personally, when I read the headline that there was a shooting at an elementary school, my thoughts immediately went to the children so knowing that none were injured would put me more at ease.