Inside An Insider Attack

So far this year, so-called insider attacks have caused the deaths of more than 50 NATO troops in Afghanistan.

Two of the people who've died-- U.S. Army Specialist Mabry Anders and Sergeant Christopher Birdwell — were killed on August 27 by a young Afghan soldier that the Taliban claims it trained.

The soldier was named Welayat Khan and his family had been surprised when Khan joined the Afghan Army because he had expressed anger when his fellow Afghan civilians were killed by NATO air strikes.

Then he turned his guns on a U.S. Army patrol and killed two American soldiers. So how did he get through the vetting process and did the Taliban use him to infiltrate the U.S. soldiers?

Phil Stewart, Pentagon reporter for Reuters, writes, "It's unclear whether the U.S. or NATO or the Afghan government forces they're training will be able to stop the next Welayat Khan before he strikes"