NBC Bay Area has learned the Santa Clara County Main Jail in San Jose recently housed an accused high-level terrorist.

Published reports show the criminal case against Armin Harcevic and five other defendants area accused of supplying money and equipment to fighters of terrorist organization, including Islamic State.

Sources tell NBC Bay Area Harcevic, just before his indictment in February, fled the Midwest and was traced to Santa Clara County, where federal officers captured him. Harcevic was then held at the Santa Clara County Main Jail's maximum security unit.

"We were surprised," Santa Clara County Sheriff's Department Spokeswoman April McHugh said. "It was unusual for us to have that level of an inmate going into custody. Very unusual."

The sheriff's department declined to comment in detail on its involvement or why Harcevic was in the county, calling it a U.S. Marshall's case. The sheriff's department said the county has no protocol in housing an accused high-level terrorist.

Despite a maximum security facility that holds about 600 inmates, including around 200 suspected murderers, Harcevic required full isolation and extra precautions during his month-long stay at the jail.

"He has two deputies with him at all times and a sergeant," McHugh said. "And when we move him from one location to another, throughout the facility all movement is stopped."

Authorities also said the exterior of the jail was closely monitored to ensure there were no attempts to get Harcevic out of custody.

Santa Clara County Board of Supervisors President Dave Cortese acknowledges he was kept posted of Harcevic being housed at the jail.

Cortese pointed out state law allows the county to keep terrorist interaction private for the community's safety.

"You don't want to inform the 'other' terrorists as to what's going on," Cortese said. "Very seldom is anybody operating in a 'terrorist environment' alone.

Harcevic and the other defendants in the case have pleaded not guilty, according to legal documents.