GALVESTON, TX --Police investigating a stabbing by the Galveston Seawall say one of the teens they thought was a victim in the attack may have been behind it. Police were dispatched early Friday morning to the 1200 block of Seawall Boulevard, where there was a report of a stabbing. When they arrived, they found two bleeding teens lying on the sand next to a white-colored Jeep. Both the men were transported to the John Sealy Hospital emergency room, where one of the teens -- later identified as 17-year-old Daniel Polk -- died. The second teen, 18-year-old Joshua Lara, was treated, released and transported back to the Galveston Police Department for a statement regarding what had happened. Detectives originally thought that Lara also was a victim of a stabbing, but after he was interviewed, investigators determined he was injured while allegedly stabbing Polk to death. Lara then was charged with murder.