FORENSIC PALYNOLOGY

Forensic Palynology is the analysis of different types of pollen grains and spores in the legal context. These spores and Pollen is not a new tool in forensic investigation. Pollen and spore analysis begin in 1916 and was first examined by Lennart Von Post. Since from 1950s, spores and pollen are used frequently in criminal investigations like theft, rape, terrorism, bombing, arson, tracing of drugs, poaching, hit and run cases etc.(Mildenhall, Wiltshire, & Bryant, 2006)

Nowadays palynology findings became important legal evidence in investigation of criminal cases and are frequently used by the countries like Australia, United Kingdom and New Zealand to solve different crime cases. From the expert’s view, fossil pollen are also being used for investigation of criminal cases along with the modern pollen, it’s been useful in determining, what happened and more importantly where it happened. (Boi, 2018)

Many papers have been published indicating the use of palynology in Forensics and also many of them suggested for the collection and preservation of different pollen samples from different parts of the world to form a palynology reference library. (Kumar, 2016) 

In general, how palynology can be useful in a criminal investigation. (Mildenhall et al., 2006)

• Establishes the relation between the suspect and the crime scene.

• Establishes the relation between an item and the crime scene.

• Traces history of travelling.

• Traces environmental information of the primary crime scene.

• Proves the presence of victim and perpetrator at the crime scene.

• Helps in shortlisting the suspect window.

• Specifies whether the crime scene is primary or secondary.

• Helps in determination of Human remains deposition duration.

 

WHY POLLENS OR SPORES AS A FORENSIC TOOL?

There is around 1.5 to 2 million different types of plants that produce pollen or spores for reproduction purpose and the best part is each of which pollen or spore is entirely unique in its own characteristics in terms of shape, size, coatings, membrane compositions, roughness, or smoothness etc. Pollen and spores of many plants can travel very large distances but most of them are in confines dispersal range of parent plant. Even the insect pollination is carried out in the particular range only. Every region’s geographical plants have their unique pollen type which is fairly called “Pollen Fingerprints” that are found only in the exact location range. (Ochando et al., 2018)

HOW THINGS WORK?

• The whole concept of pollen or spore tracing in criminal investigation is based on an important concept that is “Locard’s principle of exchange”. (Palynomorphs, History, See, & External, n.d.)

• The knowledge of production and dispersal pattern of pollen or spores is important to determine the pollen print to locate the original location.

• The basic components of crime scene investigation like soil, water, dust are present in almost every cases, the careful examination of the same can reveal the pollen samples as the evidence from the crime scene. (Kumar, 2016)

• These samples can be examined in the lab and matched with the pollen or spore samples obtained from the cloth, skin, shoes, hair, and car of the victim or the suspect indicating the presence of the same person at the crime scene.

• Just as mud found on the tire of the vehicle matches with the mud from the particular location indicating the presence of the vehicle on the same location. Similarly, if pollen found on the object matches with pollen from the plant that is found at the particular location then this indicates the presence of the same object on the same location.

• This also helps us in determining whether the crime scene is the primary crime scene or the secondary crime scene. (Boi, 2018)

• The use of ‘trace’ evidence in the form of pollen grains or spores is highly prominent in legal cases and gives a unique recognition to Forensic Palynology in today’s world.

• The new fact that also came in light is that these pollen grains or spores can be fatal for some pollen allergic people; this is also an important finding in post mortem examination as this pollen can also be used to kill someone who is allergic to these.

 

DIFFERENTIATION CRITERIA

1. Size

Each pollen and spore from a particular plant has its own specific size. No doubt that the differences in the size of the pollens are very minute (in micrometres), but can be determined by careful microscopic examination.

2. Shape

The shape of each pollen and spore from different plant is quite different from each other. Some of them are triangle in shape; some of them are round, oval and also irregular in shape. Some of them have smooth surfaces while the other has the rough one; this is based on the mode of their dispersal (Figure 1.1). (Mezzonato-Pires, Mendonça, & Gonçalves-Esteves, 2015)

                                       

(Figure 1.1) Different shapes of pollen grains(Mezzonato-Pires et al., 2015)

3. Membrane composition

Biochemical analysis of the cysts (membrane) of the pollen grain sand spores revealed that no two pollen or spores have same membrane composition and also this membrane composition is entirely specific for a particular species of plants. (Mezzonato-Pires et al., 2015)

4. Abundance and dispersal

This is based in the mode of dispersal of pollen and spores that are either they are dispersed either by wind, water or animal. This dispersal range in indirectly based on the species of plant as well, for example, 95% of pollen of anemophilous (Plants that use animals for dispersal of their pollens) plants are found within the range of 2 km of the parent plant in some cases within the range of 100 m of the parent plant. However, the glitch in this finding is that pollens dispersing by the speedy winds and fast-flowing water can reach up to dispersal range of 100 km. (Mezzonato-Pires et al., 2015)

CASE STUDIES

1. Sweden Murder Case (1959)

This case is efficiently determining the use of palynology in the specification of the primary and secondary crime scene (Figure 1.2). (Bryant, n.d.)

A woman was murdered in Sweden in her house. The soil sample washed from the victim’s cloth was collected and sent to a palynologist at the University of Sweden for examination. The palynologist found that the sample of pollen obtained from the victim’s clothing did not match with the pollen sample from the dirt on the floor of the crime scene (control sample).

                                                          

(Figure 1.2) Picture of a victim(Bryant, n.d.)

Finally, the palynologist gave the report that the crime scene where a victim’s body was found was the secondary crime scene as the victim was killed at some other location and after death dumped in her house.

 

2. Austria Murder Case (1959)

A passenger from a boat which was gone off for sightseeing was missing in Dambe river of Vienna. The only person with him on the boat was his friend and business partner. But, when police interrogated him, he denied knowing anything and claimed that he was not there when his friend got disappeared. (Bryant, n.d.)

His room and office was searched by the police and the dust evidence was sent to the forensic lab for examination, here the forensic expert transferred the pollen found in the dust to the palynologist. The palynologist found the presence of Miocene – age pollen grain of Carya plant and on search police found that there is only one spot at sightseeing location where such pollen can come in contact with humans.

                                          

(Figure 1.3) Dambe river of Vienna(“(65) Pinterest,” n.d.)

The suspect was bought at the same location, He was shocked and finally admits that he killed his friend and buried his body in a shallow grave.

3. Illinois Murder Case (1986)

A farmhouse was devastated; a farmer was kidnapped for money and further was killed by the perpetrator. His truck was found stuck in the mud and was burned few miles north from the farm. (Bryant, n.d.)                                                 

In a range of 50 miles, a thief was arrested for trying to rob a liquor shop. In jail, the thief told his cellmates that he could not get arrested if his truck was not stuck in the mud, this information reached to the jailer. The thief was bought to the truck stuck location but he denied for being the owner of that truck.

The investigating officer took some dust samples from the burned truck location and also he took some dust sample from the nearby maize farm and sends it to the lab for examination with the control sample (dust sample obtained from the thief’s cloth). From lab, the pollen was obtained from three of the dust samples and send to the palynologist.

After examination, the palynologist gave the report that three of the samples match with each other indicating that the thief was present at the burnt truck location and during further examination, the fingerprints from the farmhouse was matched with the thief and found that he was the perpetrator. This person was then charged for kidnapping and murder and sent for life imprisonment.

Forensic palynology played a key role in this case.