UPDATE: 3:30pmPolice have arrested one suspect from Laredo in connection with a violent armed robbery at a Robstown convenience store that left a man seriously injured Tuesday afternoon.According to Robstown Police Chief Mike Tamez, two masked gunmen from Laredo had been following their victim, who was conducting business at the store. The suspects, armed with an AR-type rifle and a shotgun, approached the man as he exited his vehicle."We believ…