In a symbolic victory, Clinton took 59 percent of the Nebraska vote Tuesday.
He will take a majority of West Virginia’s 29 pledged delegates.
“His supporters have to behave and not cause trouble," Ed Rendell said.
Both Clinton and Sanders reserved five-figure ad buys in the island territory.
Sanders had already won 25 of the state's delegates on election night.
Bill De Blasio, who led Clinton's Senate campaign in 2000, eventually endorsed her.
Sanders said there are states that still need to be heard from in the primary.
Sanders invited two undocumented immigrants on stage in Kentucky.
The win helps him gain ground as he tries to keep Clinton from clinching the nomination.