Pind Sammelan or Spindi is a ritual performed in Hinduism on the 13th day of death of somebody. This ritual is performed to place the departed soul with the ancestors and God. It is believed that before the ritual the departed soul is a preta (evil spirit), and after performing this ritual, the soul will become "pitr" (good spirit) and will be included in the ancestors.
^K. S. Singh; Amir Hasan; B. R. Rizvi; J. C. Das (2005), Uttar Pradesh, Manohar, 2005, ISBN978-81-7304-114-3, ... Ashes of the dead are immersed in a river, preferrably [sic] Ganga. The thirteenth day or final day of mourning is known as terahvin. It can be held any day after the ashes are immersed though generally is observed no later than the thirteenth day. It is a way of bidding goodbye to the soul. Daan, that is, gift of a new bed, shoes, clothes, quilt, ...
^Madan Lal Sharma; A.K. Bhatia (1994), Haryana, Anthropological Survey of India, 1994, ISBN978-81-7304-091-7, ... On terahvin, five pandits are called to perform purificatory puja and havan. Brahmans are treated to fried food, sweets and also given cash and presentations like a string-cot, bed, a stick, juti (shoes) and four or five utensils by way ...