Rosalind Rena Hill, 65, of Waco, pleaded guilty Thursday to first-degree felony arson in an April 2015 incident. She threw gasoline on Vivian K. Walker and lit her on fire. A court sentenced Hill to 15 years in prison after serving more than seven years. Walker, then 45, was burned over 40 percent of her body and died from complications from those burns in October 2016.