An anonymous donor has pledged $10,000 to the Surfrider Foundation in an effort to help indict the killers of Hawaiian monk seals found dead last year on Kaua'i and Moloka'i, the Garden Island newspaper reported.

A $5,000 reward will go to anyone who has information which could lead to the arrest and conviction of the person involved in slaying the male monk seal discovered floating off Kaunakakai on Dec. 14.

Some $7,000 will now be offered to those with information regarding the male seal discovered dead April 19 at Kaumakani, in addition to the $5,000 reward put up last month by the National Oceanic and Atmospheric Administration.

"There are people out there who are still really mad that somebody's doing this, and they're willing to give big money to resolve this," Kauai Surfrider's Carl Berg said. "We really want to find out what's going on, and we really want people to understand these are nature's creatures."

Only about 1,100 monk seals remain throughout the Hawaiian archipelago, with about 115 traversing the main islands, NOAA Marine Mammal Response Coordinator David Schofield said.