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.