2.1 The DNA profile

In Dave’s case, the Forensic Biologist would examine the baseball bat and any clothing recovered from the victim / suspect, testing any red / brown staining for potential blood. A Blood Pattern Analyst may be able to interpret the distribution of staining on the baseball bat and in the locker room to reconstruct how the blood may have come to be where it was found. A sample of the blood on the baseball bat would be analysed for DNA. DNA analysis could also be performed on samples from the baseball bat handle.

Research has shown that it is possible for a person to handle an item and leave very little / no DNA behind, or for a person’s DNA to be transferred to an item / surface without direct contact – a process known as secondary or tertiary transfer (DNA Judicial Primer, 2025; van Oorschot et al., 2019).

A DNA profile generated from the swab taken of the blood on the baseball bat and from the baseball bat handle would be compared with a reference DNA profile from Dave.

In our case, the DNA profile obtained from the swab of the blood on the baseball bat was indistinguishable from Dave’s DNA profile. This would be reported as the DNA profile matched the DNA profile from the victim Dave.

The DNA profile obtained from the swab of the handle of the baseball bat did not match Dave’s DNA profile and was unidentified. This DNA profile was then compared against DNA profiles held on the UK National DNA Database, however no match was returned. The interpretation of these results will be covered in Week 3.