A criminal group has held computer systems for the city of Baltimore hostage for nearly a month — paralyzing everything from email to the real estate market to the payment of water bills. But what residents don’t know is that a major component of the malware used to shut down the system was developed nearby by a federal government agency. Guest: Scott Shane, who covers national security and the U.S. intelligence community for The New York Times. For more information on today’s episode, visit nytimes.com/thedaily. Background reading:People involved in the investigation say the N.S.A. tool, EternalBlue, was found in Baltimore’s network by four contractors hired to restore computer services. The N.S.A. says that’s not the case. Cybercriminals have been targeting other vulnerable American towns and cities, from Pennsylvania to Texas, in ways that could disrupt local governments for months.