The Suisun City emergency declared by local officials followed a cyberattack that forced the Northern California municipality to shut down its information technology network, disrupting some communications used by public safety agencies. The incident has placed the California city of roughly 30,000 residents among communities confronting the growing threat of cyberattacks against essential local services. 

The Suisun City Council declared a state of emergency Saturday after the attack compromised the city's computer systems. Officials said the network shutdown was necessary to contain the threat and preserve potential evidence for a federal investigation into the incident. 

Although the Su...