Day into Night - Testing the Device

As the author of the Porter Cassel mystery series, I do extensive research for both plot development and to ensure the technical accuracy of forensic details. Part of the research is developing and testing potential devices. In the first book in the series – Day into Night – a time delay device is used by a serial wildfire arsonist. I built and tested this device. Details of the test are included below.

Disclaimer: The information is provided only for reader interest. These tests are dangerous and should never be replicated by the reader. Fires are unpredictable and can cause serious injury, death, or extensive property damage. The setting of fires that cause injury, death, or extensive property damage is a serious criminal offense.

The Device

The purpose of the device is to provide a time delay and an explosive distribution of accelerant within a brush pile.

The device consists of a long cigar inserted through a cardboard ash sleeve, which is fitted into the lower portion of a cut-off plastic pop bottle. The pop bottle contains gunpowder. The device sits in a metal pan filled with diesel.
The device is loaded and placed into the brush pile.

The Test

The device is hidden within the brush pile and the cigar is ignited.
Once the cigar burns down to the gunpowder, a canon-like blast results, accompanied by a white cloud of smoke. The explosion scatters the diesel and the brush pile is quickly engulfed in flame.

The Evidence

Once Porter Cassel, the fire investigator arrives, the pile of brush has been reduced to ash, and all that remains is the scorched cake pan, filled with ash and a black wafer of burned plastic.

The pan, as would be found in-situ. With a larger brush pile, the pan would be completely covered in ash.
The black plastic remnant as found in the pan.
Close view of the black plastic remnant.

One Careless Moment - Testing The Device

As the author of the Porter Cassel mystery series, I do extensive research for both plot development and to ensure the technical accuracy of forensic details. Part of the research is developing and testing potential devices. In the second book in the series – One Careless Moment – a fusee is used by a wildfire arsonist. Details of the test are included below.

Disclaimer: The information is provided only for reader interest. These tests are dangerous and should never be replicated by the reader. Fires are unpredictable and can cause serious injury, death, or extensive property damage. The setting of fires that cause injury, death, or extensive property damage is a serious criminal offense.

The Device

Fusees are typically used as signal flares, or used by firefighters to burn-out along a fire line, and come in various lengths which correspond to burning times. This suggests that a fusee would be a logical time-delay device for starting a fire.

The Test

The purpose of the test was to determine at what point during the burn process that surrounding fuel would be engaged. The fusee was propped at a near vertical angle. Straw was used to replicate the fine fuels that might be found on the forest floor.

Commencement of the test. The bricks are for support during the test. In the field, local material would be used.
The fusee has burned down approximately half-way when jetting from the sidewall, produced by hot gas release, ignites the surrounding fine fuel.
The fine fuel quickly becomes fully engaged.
The fusee continues to burn after the fire has progressed away from the ignition source.

The Evidence

A white brittle residue is all that remains of the fusee. The residue appears ceramic, and has a sulfurous odor.
Fusee striker cap which might be dropped during escape by an arsonist.