Officials are refusing to discuss Thursday's search of Syed Raheel Farook's residence

Credit: Will Lester/The Inland Valley Daily Bulletin/AP

Federal agents spent four hours on Thursday combing through the Corona, California, home of Syed Raheel Farook, the older brother of the male shooter in last December’s San Bernardino massacre.

Federal Bureau of Investigation spokeswoman Laura Eimiller tells PEOPLE the raid was sanctioned in a search warrant that has since been sealed by a judge.

Eimiller says that seal prevents her from discussing Thursday’s raid in any detail.

“I can say that a search warrant was executed at that residence in California,” Eimiller says, “We’re still seeking evidence as part of this ongoing investigation.”

Calls to Farook’s cell phone and home were not returned on Friday.

Farook’s brother, Syed Rizwan Farook, and his wife, Tashfeen Malik, shot and killed 14 people on Dec. 2 in a terror attack targeting a holiday celebration at the Inland Regional Center in San Bernardino. Many of the dead had worked with the shooter at San Bernardino County’s Department of Public Health.

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Eimiller refused to describe what evidence was collected during the search, but noted Thursday’s raid yielded no arrests – despite media footage showing two unidentified people in handcuffs.

Agents placed the two subjects in restraints as a precaution, Eimiller says.

Camera crews also caught agents exiting Farook’s house during Thursday’s operation, with investigators seen lugging armloads of thick manila envelopes and a computer tower to evidence trucks.

According to records, Farook enlisted in the Navy from 2003 to 2007, earning several medals during his service. The raid came one day after Apple’s CEO Tim Cook released a statement to iPhone customers, announcing their intent to fight a judicial order directing the tech giant to aid the FBI in hacking the terrorist’s phone.