Url changed from https://www.businessinsider.com/killer-drone-hunted-down-hum..., which points to this.

The original source looks to be https://www.newscientist.com/article/2278852-drones-may-have..., but that's hardwalled and so off topic here (https://news.ycombinator.com/newsfaq.html, https://news.ycombinator.com/item?id=10178989). If there's a better accessible source, we can change it again. I've used the NS headline since it's the most neutral.