Although it’s difficult to separate the insect from the dark background, I can say that it is a dragonfly. Although these insects are most commonly seen near water, now and then they also fly during the daylight hours in gardens and landscapes. My best guess for the identification of your colleague’s insect is a male common whitetail skimmer, Plathemis lydia. Each forewing is colored with a combination of a large black square flanked by clear see-through sections. See this http://bugguide.net/node/view/603 and  this http://www.whereartmeetstheheart.com/dghdragonfly.shtml