Which group may typically engage in the authentication of handwriting as a witness?

A lay witness with personal knowledge is typically the group that may engage in the authentication of handwriting. This is because a lay witness can provide testimony based on their direct observations or interactions with the individual whose handwriting is in question. If they have had sufficient encounters with that individual's handwriting in a context where they became familiar with it, they can articulate their recognition and authenticate it as belonging to the specific person.

The legal system allows for this type of testimony from non-expert witnesses because personal knowledge does not require specialized training; rather, it relies on the witness's own experiences and interactions. This is in contrast to other groups such as the general public, who may not have the necessary personal connection to the handwriting being scrutinized. Legal professionals and private investigators, while they may possess expertise or investigatory skills, are not inherently qualified to authenticate handwriting without personal knowledge of the individual's style.

Therefore, a lay witness can provide admissible testimony regarding handwriting authentication in court, assuming they can establish their familiarity with the handwriting and their basis for identifying it.