The NYPD says its Bomb Squad locked down the New Millennium Business Academy Friday as hostage negotiators worked to get a computer teacher, who barricaded himself inside a classroom, to surrender.

Francisco Garabitos, 55, was told not to come back to work after being investigated for hitting a student on Thursday. When Garabitos showed up at school Friday morning, Principal Dorald Bastian called 911 and that's when the three-hour standoff got under way.

The Hostage Negotiation Unit responded to the scene while teachers evacuated the students from the school. All of the students got out safely and no explosives were found inside.

According to investigators, it took three hostage negotiators and a teacher?s union representative to convince Garabitos to surrender. Investigators took Garabitos in for questioning.

Click 'Next' on the video player to view each segment.