Police have named a fifth suspect in connection with last month’s fire at the National Information Resources Service in Daejeon, which caused major disruptions to government computer systems.

The Daejeon Metropolitan Police Agency said Friday that it was investigating an additional construction worker for occupational negligence in the case.

Investigators also said they'd obtained testimony indicating that workers had failed to shut down a secondary power source during the relocation of lithium-ion batteries.

The blaze erupted about an hour later on September 26, destroying hundreds of batteries and servers and paralyzing 709 government systems.

As of Friday, 30-point-six percent of the affected systems had been restored, including 75 percent of top-priority networks.