To understand 17th century Massachusetts, one needs to understand that the Puritans sincerely believed that Satan and witches walked the earth. The following demonstrates that superstitious evidence was used to render a conviction in 1692, and that there is a major difference between seventeenth century British Law and the Law today. .
It all started during the winter of 1691 when a group of girls and women began to meet nightly with Tituba, a West Indian servant. Soon the members of the circle began to show hysterical symptoms. They crawled under tables and chairs, made strange sounds, and had horrible nightmares. Over forty people in 1692, including Tituba confessed to being witches and in some cases those confessing accused others. A witch was someone who had entered into a covenant with the Devil, instead of with God. This person presumably gained strange powers, could afflict or hurt someone secretly, could make an animal or a person fall sick or even die, and/or could take on the form of an animal. They also engaged in behavior that would have been prohibited under normal circumstances, like sex and dancing.
The irony is that only those who did not confess to being witches were actually tried and convicted. With spectral evidence, your accuser is the only person who verifies your "crime." Spectral evidence is evidence that a spirit of the accuser had afflicted its victim. The judges often believed in spectral evidence. It overrode the accuser's alibi because the judges blamed the witchcraft on their spirits. The afflicted girls provided the evidence while sometimes other confessed witches gave supporting testimonies to others being witches. Generally, citizens made complaints against individuals, who were then brought before the court. When judges felt that there was enough evidence for a trial, the accused were put in jail until their trial. A formal trial by jury could possibly follow.