Mediumship is a specialization some telepaths use to detect the mental impressions left by the deceased, effectively forming a telepathic connection to the dead. Everybody leaves mental impressions as they live. Strong emotions leave stronger mental impressions. Murder victims leave very strong mental impressions, especially on their murderers and murder scenes. The DNA Alternate using mediumship can detect these mental impressions.
Death leaves one of the strongest imprints behind. Telepaths leave larger imprints than others, especially when they use their abilities. If the Alternate with mediumship is present during the death, the mental imprint can be corrupted. Imprints take time to form, depending on the strength of the emotion. It could take anywhere from a few days to many years before an imprint can be detected. Ones that only take days tend to be the ones that are left by telepaths or murder victims. Imprints appear as moments in the life of the person who left them, specifically whatever event caused the impression. The imprint is not always complete. Fragments are more common than full imprints.
Many Alternates develop the belief that they have a mystical connection with the deceased who left the imprints. Many describe it as feeling like the deceased is trying to contact them. This may lead to the development of psychosis, or more severe mental disorders. They may begin to imagine imprints where none exist.