Agents were at the Hattie Mae White Educational Support Center since just before 8 a.m.
Authorities walked out of the building with three large boxes and an Apple Mac computer monitor and loaded the items into a car.
It wasn't yet known if the activity at Busby's home was related to the FBI's presence at HISD.
Original post, 11 a.m.: The FBI says it is at the Houston Independent School District's administration building conducting an investigation Thursday morning.
The agency said it wanted to assure the public there is no danger to HISD students, staff or the greater Houston community.
It's not clear what they are investigating, but the FBI said it has no further comment at this time.
SkyEye13 also spotted authorities outside of HISD's Chief Operating Officer Brian Busby's house on Thursday. Busby, a 21-year veteran with HISD, has served in his current post since December 2016.
In his role, Busby oversees an annual operating budget of more than $260 million and leads a workforce of more than 7,000 employees from seven major departments, including construction, transportation, nutrition, police, facilities, support and strategic engagement and outreach.
The FBI Houston Field Office released this brief statement on the matter: "The FBI is conducting court authorized law enforcement activity at the Hattie Mae White, HISD Administration Building. We want to assure the public there is no danger to the HISD students, staff or greater Houston community. We will provide any additional information once it becomes public. We have no further comment at this time."
HISD released the following statement on the matter: "HISD can confirm that the FBI is in the Hattie Mae White Educational Support Center this morning regarding a court authorized law enforcement matter. The district is fully cooperating. There is no danger to students, staff or the community."