Officials in Yellowstone National Park in Wyoming are searching for a man they believe committed suicide by jumping into a river and going over a 300-foot waterfall.

They say the 20-year-old man was last seen Tuesday afternoon jumping over the railing at an observation platform over the Yellowstone River. Witnesses say the water carried him over the river's Lower Falls.

The search for the man continued Wednesday but park officials said they presume the man died.

Authorities did not release the man's name.