There appear to have been at least two involved, one neutralized, one now cornered, and possibly a third man, the man in the picture, who they call a 'person of interest'.

Update:

This man turned himself in and has been determined to not be a suspect by police, and has been released. Police were looking at him because he was wearing a camo shirt and had an AR-15. But Texas is an open carry state, so he had the legal right to carry. 

3 other suspects are in custoday, one committed suicide.