What is Sutak
Sutak means the Impurity. Ritual periods during times of births (this is called Pindroo) and deaths in a family, in which one is considered Sutak
The explanation is derived from Garud Puran which is a dialogue between Lord Vishnu and Garuda.
It deals with present life and afterlife, it deals with the essential ceremonies required to be performed after the death of relatives and the consequences of not performing such ceremonies.
Its stated in the Garuda Purana that when the death of a near relative takes place within the period of Panchak, within one year, five members of the family can die if proper ceremonies are not performed after the death.
Such proper observances of the procedures before and after cremation means that the Preta (the soul of the deceased) reaches Param Gati .
It is believed that, upto the 10th day, the deceased still continues his relation with his house and surrounding. Therefore the deceased is termed as Pret, which means one who has departed, but who has not yet reached the decision of Dharma Raja.
On the eleventh day, Brahma, Vishnu, Rudra and Yama are invoked, with Vishnu as the special witness. In their presence the deceased is offered pindas. On the twelth day sapindi karam is performed where a rice ball is chopped into 2 pieces. Another pind (rice ball) is put in the middle of the two pieces made earlier one. This middle pind is for the deceased (preth). All this is then combined and at this point the soul then follows the decision of Dharma Raja.
The relatives are then freed from the sutak and can then perform their daily puja. These rites are also sanskaras (antyesthi) on the soul to lead it to God.