Nightly News | October 04, 2012
>>> border patrol agent killed earlier this week along the arizona-m arizona-mexico border. nbc's mark potter is in sierra vista where he liveded with his family. good evening.
>> reporter: good evening to you, brian. federal investigators tell nbc news that based on evidence they've found so far, they are looking into whether this shooting may have been a friendly fire incident . agents shooting at each other. he was shot and killed early tuesday morning while responding to desert sensors that track illegal movement across the border. two other agents were with him. one was wounded. they had reported being fired upon earlier. officials blamed the shootings on armed criminals and mexican authorities say they have made two arrests relalted to the case. while u.s. investigators say they have reached no conclusions and still have a lot of work to do, they cannot rule out the possibility this was a friendly fire .
>> mark, thanks.