LOGAN, Iowa (AP) – An Iowa teen charged with murdering his 5-year-old foster brother plans to use an insanity defense when his case goes to trial this month. Court documents filed in September indicate the defense plans for 18-year-old Cody Metzker-Madsen, who was declared competent to stand trial in April. He is charged with first-degree murder in the August 2013 death of Dominic Elkins, of Atlantic. Metzker-Madsen pleaded not guilty to the charge and opted to have his case decided by a judge.

Authorities say Elkins was killed while the boys were playing outdoors at their home near Logan, in western Iowa. He died as a result of blunt-force head injuries and drowning. Psychology experts who examined the teen say he has developmental problems.

Metzker-Madsen’s mother used methamphetamine while she was pregnant with him.