JACKSON, Miss.--A former Democrat Senator from Pennsylvania is being remembered by the State of Mississippi today. Arlen Specter died Sunday at age 82. Gov. Phil Bryant ordered all flags at half staff until sunset today.

Specter was a moderate, who began his political career as a Democrat, switched to the Republican Party in 1965, then, after 44 years, became a Democrat again in 2009.

He is best remembered for his service on the Warren Commission, set up to investigate the death of President John F. Kennedy. It was he who devised the "single bullet theory".

In his later years, Specter would become a critic of some Republican policies, notably parts of the Patriot Act. He criticised Pres. George W. Bush for wiretapping without warrants.

Specter died from non-Hodgkin's lymphoma complications at his home in Pennsylvania.