A search will resume Saturday morning for a missing 20-year-old man, who was swimming today in a pond along the Wailuku River below Rainbow Falls on Hawaii island.

The Hawaii County Fire Department deployed rescue divers and searched the area where he was last seen, but did not find him.

Witnesses reported the man appeared to be fatigued while swimming. They saw him go underwater, but he never resurfaced, the fire department said in a news release.

The 20-year-old was with three other swimmers who were on shore when the fire rescue personnel arrived at about 5:57 p.m.

The fire department got the call at 5:48 p.m., and sent seven units, including its helicopter and medic units for a total of 15 personnel.

The search was suspended due to darkness.