The 363 FDNY members murdered that day.
The number is actually much higher, given how many first responders have died and will die from related illnesses. One recent study showed that first responders are 15% more likely to get a whole range of cancers and illnesses. Carbon Nanotubes Found in the Lungs of World Trade Center Patients and Dust Samples - 'carbon nanotubes' come from materials that have been produced at the nano scale. Like the thermitic red chips. (Harrit. 2009. Bentham Open Access Chemical Physics Journal)