FORT LAUDERDALE, Florida (CNN) -- Esteban Santiago, the man charged with killing five people at the Fort Lauderdale airport, told FBI agents he carried out the attack on behalf of ISIS, FBI special agent Michael Ferlazzo testified at Santiago's bond hearing Tuesday.
The agent did not elaborate on whether Santiago was purporting to be linked to ISIS or simply inspired by the terrorist organization.
Federal authorities in Alaska said Santiago told them prior to the attack that he was hearing voices and that his mind was being controlled by the CIA. Santiago made no such claim during the six-hour interview conducted shortly after the January 6 shooting at Fort Lauderdale-Hollywood International Airport, Ferlazzo testified.
ISIS has not claimed responsibility for the attack.
Ferlazzo, who conducted the interview, said only that Santiago claimed to be fighting for ISIS and that he'd been in touch with like-minded people via jihadi chat rooms who were planning attacks as well.
Santiago is charged with using and carrying a firearm during and in relation to a crime of violence; performing an act of violence against a person at an airport serving international civil aviation that caused serious bodily injury; and causing the death of a person through the use of a firearm.
The latter two are punishable by death, while the first charge carries a maximum penalty of life in prison.
Authorities have said that Santiago confessed to the mass shooting, which they said he perpetrated after disembarking a plane from Anchorage and collecting a checked bag containing a Walther 9-millimeter pistol and two magazines.
At Tuesday's hearing, the defense did not argue the prosecution's assertion that Santiago posed a flight risk, as well as a danger to the community, and said that the defendant was prepared to be detained throughout his trial.
The judge ruled he be held without bond. His next court appearance is January 30.