An individual is presumed to have died leaving no heirs if for the seven-year period preceding the court's determination:

1. (1) a lawful claim to the individual's property has not been asserted; and
2. (2) a lawful act of ownership of the individual's property has not been exercised.

Acts 1983, 68th Leg., p. 3585, ch. 576, Sec. 1, eff. Jan. 1, 1984.