Seems too broad a job for one person, whether a foreign intelligence plot or a domestic job. Required rôles - Organiser-manager, Biologist, Materials Scientist, Courier. Minimum 2 people, since skills in bio and materials engineering would not be located in the same person. Probably more than 2. Some of the other rôles might or might not be combinated into one person.
<< And Who's puttin' the bugs in their ears? >>
News reports said that Bedlington gave them the pond bug and he got it from Hatfill himself. I do not think news reports said from where the Berry info came.
It is with utmost clarity that the effect of the pond draining was to expose the FBI to ridicule. This would discourage further consideration of the domestic theory, since the lesson is that it leads one into ridicule. This effect was totally predictible so one can judge that it was planned for that effect.
"Seems too broad a job for one person"
Some folks can walk and chew gum at the same time:
"Bioengineering is the discipline of engineering that applies principles and methods from engineering, the life sciences, and the medical sciences to understand, define, and solve problems in medicine, physiology, and biology."
I'd wager there are a few that can walk, chew gum,plan a meal and mail a few letters - at the same time.