A 21-year-old man was missing in the Potomac River on Saturday night after jumping in below Great Falls. The incident came days after a 19-year-old man died in the same treacherous stretch of the river.

In Saturday night’s incident, the man apparently jumped into the water near Bear Island, and three others jumped in to try to save him, according to Assistant Chief Scott Graham, a spokesman for the Montgomery County Fire and Rescue Service.

The others reached shore safely, but the 21-year-old was not found, Graham said. He said efforts to locate him would resume Sunday.

In another development, a friend of the man who died Monday in the same area said that Ngo Tekwe Forchick, 19, had not been swimming there, as previously reported.

The friend, Erika Fuentes, said Forchick had fallen into the water. He had his arm around a co-worker from the Riderwood retirement community when both slipped, the friend said.

Another co-worker tried to save them but was unable to rescue Forchick, who could not swim, Fuentes told a reporter Saturday. His body was found Wednesday.