News of Park's alleged execution follows reports that North Korea's second most powerful official after leader Kim Jong Un has been punished.
General Hwang Pyong So has not been seen in public for two months.
A report based on interviews with 375 defectors identified up to 333 killing sites in the hermit state.
Charges punishable by death reportedly include stealing farm produce and distributing South Korean media.
Two officials were executed publicly, according to a South Korean newspaper.
"Excuses or reasoning doesn't work for Kim Jong Un."