2008 Woodie Awards
RIDEM analyst discusses role of metal detectors in criminal investigations
Jeff Sullivan
Issue date: 2/12/08 Section: Campus
02/12/08 - An agent of the Federal Bureau of Investigation and criminal investigator working for Rhode Island discussed the procedures of crime scene investigation and elaborated on the usefulness of metal detectors in investigations at Pastore Hall last Friday.
David Thatcher, of the Rhode Island Department of Environmental Management's Office of Criminal Investigations, never thought his childhood love of treasure hunting with a metal detector would get him a professional job as a treasure hunter, let alone one with the state.
He said the main reason that his skills with the machine are useful to investigations is that it is a perishable art. Thatcher said that because it is not considered an important tool in every investigation, most investigators are either not properly trained or not experienced enough in the machine, which he says usually takes about 50 hours of practice.
William Rose, a special agent for the FBI Boston office, pointed out the usefulness of the metal detector in finding evidence in a large crime scene.
"Crime scenes come in many different sizes," he said. "They can be as big as a football field and in some cases, as in the Egypt Air 990 incident, you can have 300 or so bodies, it can really be a morgue."
During his speech, Thatcher asked the audience what a metal detector was.
"Some from the East Bay think it's a quahog finder," he joked.
He said that a metal detector actually beams out a radio signal into the earth and reads the reflected signal. The signal is weakened when it hits a metal object and from the dissipation of the signal it can detect numerous facts. The newest models can identify certain objects, such as cans, coins and scrap metal, and can even tell the denomination of the coin.
Rose also discussed crime scene investigation and the importance of knowing how to use a metal detector in the field.
"A metal detector is especially important if you have to go back to a crime scene after five or six years [of the initial investigation]," he said. "If there are no landmarks, even sketches can be inaccurate, but if you drive a metal stake into the ground one can find the [original] position of the evidence without any dispute from a defense lawyer."
The metal detector has been crucial in criminal investigations because there are certain pieces of metal that never leave the original area of disposal on a cadaver. Thatcher said that pant zippers, fillings and rings are crucial because unlike bodily fluids that dogs sense, they are rarely moved naturally.
He related a story from a few years ago in which a man claimed to have been an eyewitness to the killing of the infamous Boston gangster James J. 'Whitey' Bulger. Cadaver-scenting dogs were sent in and were reported to have found a body.
"The dogs only pick up blood and [a few other select fluids]," he said. "I mean someone could have dropped a condom and they will scent it as a cadaver."
Despite no reliable human metal objects being found, the investigators dug up the entire area to where the witness reportedly saw Bulger and his girlfriend being murdered and buried and found absolutely nothing.
David Thatcher, of the Rhode Island Department of Environmental Management's Office of Criminal Investigations, never thought his childhood love of treasure hunting with a metal detector would get him a professional job as a treasure hunter, let alone one with the state.
He said the main reason that his skills with the machine are useful to investigations is that it is a perishable art. Thatcher said that because it is not considered an important tool in every investigation, most investigators are either not properly trained or not experienced enough in the machine, which he says usually takes about 50 hours of practice.
William Rose, a special agent for the FBI Boston office, pointed out the usefulness of the metal detector in finding evidence in a large crime scene.
"Crime scenes come in many different sizes," he said. "They can be as big as a football field and in some cases, as in the Egypt Air 990 incident, you can have 300 or so bodies, it can really be a morgue."
During his speech, Thatcher asked the audience what a metal detector was.
"Some from the East Bay think it's a quahog finder," he joked.
He said that a metal detector actually beams out a radio signal into the earth and reads the reflected signal. The signal is weakened when it hits a metal object and from the dissipation of the signal it can detect numerous facts. The newest models can identify certain objects, such as cans, coins and scrap metal, and can even tell the denomination of the coin.
Rose also discussed crime scene investigation and the importance of knowing how to use a metal detector in the field.
"A metal detector is especially important if you have to go back to a crime scene after five or six years [of the initial investigation]," he said. "If there are no landmarks, even sketches can be inaccurate, but if you drive a metal stake into the ground one can find the [original] position of the evidence without any dispute from a defense lawyer."
The metal detector has been crucial in criminal investigations because there are certain pieces of metal that never leave the original area of disposal on a cadaver. Thatcher said that pant zippers, fillings and rings are crucial because unlike bodily fluids that dogs sense, they are rarely moved naturally.
He related a story from a few years ago in which a man claimed to have been an eyewitness to the killing of the infamous Boston gangster James J. 'Whitey' Bulger. Cadaver-scenting dogs were sent in and were reported to have found a body.
"The dogs only pick up blood and [a few other select fluids]," he said. "I mean someone could have dropped a condom and they will scent it as a cadaver."
Despite no reliable human metal objects being found, the investigators dug up the entire area to where the witness reportedly saw Bulger and his girlfriend being murdered and buried and found absolutely nothing.