The dolphin is one of two that were found dead in the Northern Gulf of Mexico after being shot in the last month; it was found washed up on Orange Beach, Alabama, on December 7, with the arrow still sticking out of its side.
Right after Thanksgiving, another dolphin was found on Miramar beach, Florida; that one was pregnant and had been shot and killed with a small caliber gun.
The reward, initially $5,000, now stands at $20,000 after several agencies put their own money into the pot to try to encourage people to come forward with information.
The National Oceanic and Atmospheric Administration has been coordinating efforts to find the people responsible for the shooting. Both dolphins are thought to have survived for several days before their injuries killed them.
“This intelligent, social creature experienced tremendous suffering from this senseless act,” said Mindy Gilbert, Alabama state director for the Humane Society of the United States in a news release. “We are grateful for NOAA’s work to investigate this heinous crime and are hoping someone with information will come forward.”