And although this is a fire scene, it is also a crime scene, which means a large unit of crime scene investigators is present, working from a tent at the corner of West St. and Liberty. (p. 194)
NYPD Detective first grade Hal Sherman: "At Ground Zero the CSU is responsible for photographing the site, recovering physical evidence, documenting body parts and any other physical evidence like weapons or a wallet, manning the temporary morgue at the site (as well as the city morgue up on 28th Street), inspecting debris that leaves the site, and inspecting debris as it gets sifted out at Staten Island. ...All evidence is documented– airplane parts were essential to the beginning investigation, but now they look for hair, fibers, glass particles, semen, ballistics. ...We ID every part. Pillars and beams are swiped for hair, tissue and blood, evaporated body evidence. We have two police officers with mortuary degrees, and they are either in the medical examiner's office or the police lab, because you must be a sworn police officer to take evidence.
If you step on a fly ten times there will be nothing left. And here we have no couches, no computers, no chairs, no glass. Any small trace of anything is evidence. Anything to bring closure to the families. Human body part, clothing, jewelry, equipment and tools, anything. If there ever is a trial, we will be prepared. We've been here from day 1, and we'll be there well after the regular police officers go home, when everyone is packed up and gone." (p. 326-327)
There are two dump sites. One is in Fort Hamilton, Brooklyn, and the other is in Great Kills, Staten Island. At each location police Investigations Unit detectives and FBI agents are spotting and sifting through every truckload, searching for the flight recorders of the planes and for any remains of the victims.