John Jackson was executed in 1992 for killing his three children . Webb asks that prosecutor in 2004 case be investigated . Ex-prosecutor : Allegations latest `` tack '' by death penalty opponents in case . John Jackson says he tried to protect informant after case , not coerce testimony .
Cameron Todd Willingham was executed in 2004 for killing his 3 children . Innocence Project asks that prosecutor in 1992 case be investigated . Ex-prosecutor : Allegations latest `` tack '' by death penalty opponents in case . John Jackson says he tried to protect informant after case , not coerce testimony .