Grounds for challenging the results of a digital investigation can come from possible , that is, alleging that the relevant evidence came from somewhere else or was somehow tainted in the collection process.

CONTAMINATION

Explanation:

Digital investigation is the process of detecting  and interpreting electronic data on computers and mobile devices, both  software and hardware since evidence  related  to the crime may be recorded in digital form. Therefore the approach for effectively acquiring, storing and analyzing digital evidence must be quick and efficient or else Contamination which  is the introduction of items( or corrupton of files eg electronic data ) that was not previously there  can happen before investigation, during and after investigation to taint a collection or remove evidence concerning a crime.

To prevent this prevalent occurrences and produce reliable results,  it is necessary to combine manual investigation too and this involves visiting the main site of the crime for:

Proper Evaluation-This involves  noting the location of potential evidence mentally outlining how effective documentation would be carried out.

Protection involves setting up a command post to prevent contact to the  area before rerecording of evidence can take place

Documentation; this involves the use of  (videotapes. photographs and sketch) which must be carried out to ensure only the right investigations are carried out

they encountered severe weather for which they were poorly prepared.