DES MOINES (AP) - A man convicted of killing his parents and three sisters asked Wednesday that the Iowa Court of Appeals throw out some evidence and grant him a new trial.

Shawn Bentler, 24, was convicted of five counts of first-degree murder in May 2007 and is serving five life sentences. Authorities said he drove from his home in Quincy, Ill., in October 2006 and shot to death his family in their rural Bonaparte home in southeastern Iowa.

His lawyer, Theresa Wilson, a state assistant appellate defender, argued that a district court judge should not have allowed the clothing Bentler was wearing when he was arrested to be used as evidence at his trial.

A key piece of the prosecution's evidence was a pair of socks Bentler was wearing when he was arrested. On them was a drop of his mother's blood, placing him at the scene of the murders.

Wilson argued that the seizure and initial examination of Bentler's clothing violated his constitutional rights. That's because investigators with the Iowa Division of Criminal Investigation didn't have a warrant to take the clothes from the custody of the Adams County, Ill., jail. She added that they only pursued a warrant once they examined the clothes and saw blood on the socks.

Wilson said while many jurisdictions have found that defendants have a diminished expectation of privacy, "that does not mean, however, that a defendant has no expectation of privacy."

She claimed that a person in police custody would not expect their personal property to be handed out to a third party without either a consent or formal authorization.

Bridget Chambers, an assistant attorney general, argued that Bentler's clothing was lawfully seized.

Once the clothes were lawfully in the possession of Illinois police, she said Bentler no longer had a reasonable expectation of privacy, and the clothes could lawfully be released to Iowa agents for examination and testing.

She said the law doesn't require that the blood must have been seen for the clothes to have been taken as evidence by the Iowa agents.

"The bottom line is that those were the clothes the defendant was found wearing shortly after the crime, and it was the kind of crime which might well generate trace evidence," she said.

Even if the clothing was unlawfully seized, Chambers said the agents later obtained a search warrant so that "cured any illegality."

Bentler was convicted in May 2007 of killing his parents Michael, 53, and Sandra, 47, and his teenage sisters, Sheena, 17, Shelby, 15, and Shayne, 14. Prosecutors argued that the unemployed father of two wanted to inherit money from the family's successful grain elevator and lumberyard businesses.