Sheriff Danny Rigel tells The Hattiesburg American Ada Smith's white 1993 Buick was found hidden in a swampy area near Slidell, La., at around noon Wednesday.
The 95-year-old Smith was found dead in her Mississippi 589 home just north of Purvis Sunday. She died from a stab wound to the torso.
Investigators secured a capital murder warrant for each of the two suspects arrested Tuesday in New Orleans.
Twenty-two-year-old James Robert Martin and 26-year-old David Bass are being held at the Orleans Parish Jail.
Authorities had been searching for both suspects on escape charges after they walked away from the state community work center in Hattiesburg on Saturday.
Martin was serving a five-year sentence for a grand larceny conviction from Monroe County. Bass was serving a seven-year sentence for five burglary convictions from Lee County.