Law enforcement officials in Missouri confirmed Saturday James Horn Jr., a man wanted by police for killing his ex-girlfriend and her 17-year-old son, was shot and killed. Sedalia police said Horn, a convicted sex offender, had previously kept Sandra Kay Sutton, 46, locked in a wooden box on and off for months.

KSHB-TV, Kansas City, reported Sedalia police killed Horn in a shootout near the Kearn Memorial Wildlife Area in Johnson County.  Horn was killed between 11 a.m. and 1 p.m., the station reported. 

Local media previously reported the bodies of Sutton and her son were found by her brother inside a residence about 4 a.m. Thursday morning. The residence in which the two were found belongs to an unidentified family member, police said. "When officers contacted the victim, she told them the suspect routinely locked her in a wooden box inside the residence where they lived," a spokesperson for the Sedalia Police Department told Huffington Post earlier this month.

After searching the residence, officers said they found a wooden box that was "consistent" with a description Sutton had given police.  The box, according to a probable cause affidavit, was 100 inches long, 48 inches wide and 52 inches tall, Huffington Post reported. It was soundproof and contained several items, including a sleeping bag, reading materials and a bucket full of urine and feces. Sutton reportedly told police Horn had held her captive since January.

Before going on the run, Horn had been charged by local prosecutors with kidnapping, armed criminal action and unlawful use of a weapon. Police had been searching for Horn since May 1, a day after Sutton escaped the box and contacted police with the help of a neighbor. The initial call from her came April 30, around 6 p.m., KSHB reported.

This is a developing story.