JEFFERSON CITY - Attorneys argued the constitutionality of extra penalties for sex, drug and gun offenders in the Missouri Supreme Court Tuesday.

At issue is a constitutional prohibition keeping states from passing "ex post facto," or "after the fact" laws.

Article 1 Section 13 of the Missouri Constitution prohibits enactment of "any ex post facto law."

The court spent several hours discussing whether sex offenders and people with gun and drug convictions should face further "retrospective" charges after they've been sentenced.

Attorney Jerry Miller said one convicted sex offender was given a penalty that should have been unconstitutional six years after being convicted.

"He was punished for something that he shouldn't have been punished for," Miller said. "He was put in jail for almost a year. He faces up to seven years in the penitentiary on a class C felony that didn't exist when he served his five years probation."

One case heard by the judges involved a sex offender convicted back in 1998. He was indicted in 2011 for loitering within 500 feet of a public park or swimming pool, but attorneys argued that he was given a harsher sentence for a law not in existence at the time of his original crime.

Attorney Margaret Johnston said the court should have to define the term "retrospective," before people are forced to face penalties from them.

"Part of the debates for the [U.S] constitutional convention included one delegate who wanted to define the term retrospective," Johnston said. "And that was not supported by everyone. So we don't have a definition of what it is."

The court gave no indication over when rulings would be made on the cases.