Authorities on Monday investigated a shooting in which two people were killed and four others wounded after a Mardi Gras parade in a Mississippi Gulf town, police said.Officers directing traffic heard shots fired shortly after the parade ended on Sunday, Pass Christian Police Chief Timothy Hendricks said at a news conference on Monday.Two men died at the scene, he said, and four others were wounded and treated at a hospital. Two of the wounded were in stable condition on Monday afternoon and two others were released, Hendricks said.There were no immediate arrests. Hendricks said he did not consider the incident an act of terrorism, or being racially motivated."It's a horrible act," he said during a news conference webcast by WLOX TV News.He said the shootings were unrelated to the parade that drew an estimated 50,000 people to the small Gulf town about 30 miles west of Biloxi.Hendricks said multiple shots were fired, and casings that were found indicated two firearms were used. Authorities were still trying to determine whether there had been one or more assailants, he said.A vehicle containing evidence was impounded, he added.Authorities performed autopsies on the two dead men, he said. Their ages were 29 and 43 years old, WLOX reported on its website, citing the Harrison County Coroner.