“The F.B.I. searched the home of the cryptocurrency executive Jesse Powell in March as part of a criminal investigation into claims that he hacked and cyber-stalked a nonprofit that he founded, three people with knowledge of the matter said.

The investigation focused on an allegation by the nonprofit that Mr. Powell, who also founded the cryptocurrency exchange Kraken, had interfered with its computer accounts, blocking access to emails and other messages, the people said. Agents with the F.B.I. and the U.S. attorney’s office for the Northern District of California have been looking into Mr. Powell since at least last fall, three people with knowledge of the case said.”