EDINBURG, Texas—A South Texas teen convicted of killing his mother is seeking a new trial on the grounds some witnesses contradicted their official police statements.

A Hidalgo County jury convicted 18-year-old Christopher Hughes of killing his mother and sentenced him to 45 years in prison on Aug. 12.

Attorneys for Hughes say some witnesses had inconsistences in their statements during the five-day trial. The Monitor of McAllen reports defense attorneys also allege some Hidalgo County sheriff’s deputies coerced witnesses to implicate Hughes. A court hearing is scheduled for Sept. 9.

Prosecutors say Hughes shot 44-year-old Laura Hughes Doyle in April 2007 to get access to thousands of dollars in life insurance money she received after her husband died of cancer.

Christopher Hughes was 16 at the time of the slaying but was certified to stand trial as an adult.