The gunman was identified as Man Haron Monis, who once was prosecuted for sending offensive letters to families of Australian troops killed in Afghanistan.
Police quickly closed off streets in the area and offices were evacuated.
A prank call that brought a massive response in Union County, N.J., was the subject of a criminal investigation Monday.
Police were serving a warrant Tuesday on Madison Street, sources told CBS 2. The man they were looking for was wanted for the 2010 shooting of a Pace University student.
Graduation day was bittersweet for students at Hofstra University Sunday, as students carried heavy hearts for a classmate who was shot and killed in a violent home invasion.
The hostages are safe and the suspect is dead, police said.
A hostage situation persisted in Trenton, N.J., Saturday morning, after a woman and a child were found dead inside a home.
One police officer received a grazing gunshot wound and was treated at the scene. A police dog was shot in the abdomen and was in stable condition Thursday morning.