What specific event prompted people to think that witches
were living in the colony?

Ergot Poisoning.

Explanation:

Ergot is UNSAFE. There is a high risk of poisoning, and it can be fatal. Early symptoms of poisoning include nausea, vomiting, muscle pain and weakness, numbness, itching, and rapid or slow heartbeat. Ergot poisoning can progress to gangrene, vision problems, confusion, spasms, convulsions, unconsciousness, and death.

well the fact it is basically a peninsula allowed trade to come from many places, thus allowing cultural diffusion to take place. india has seasonal monsoons that merchants travel back and forth from india using the monsoons wind patterns