What is the fine-grained topic of the following text: New York, November 23, 2009—Several journalists covering relatives and supporters of a local politician who was about to file his gubernatorial candidacy on the Philippines island of Mindanao today were believed to be among those killed by a gang of armed men in Maguindanao province, according to international news reports. Only return the topic.
Journalists killed covering political event in Mindanao, Philippines