The bottlenose dolphin that washed up on Hollywood beach earlier this month was dead before it was attacked by a shark, marine officials said today, but what killed it might never be known. Blaire Mase, marine mammal stranding coordinator for NOAA Fisheries, said that the dolphin's decomposition had progressed too far for investigators to tell for certain what caused it to die.

But the shark bite marks on the dolphin's body were post-mortem, she said.The dolphin was found early in the morning on Sept. 15 by beach maintenance officials on the coast between Michigan and Buchanan streets. The 7-foot mammal was moved to a nearby sandy lot, and officials alerted police and the National Oceanic Atmospheric Administration.