COLUMBIA, Mo.—A Missouri man accused of killing his wife and burying her body in a park took the stand Tuesday to testify in his first-degree murder trial. Joseph Elledge is charged with first-degree murder in the death of 28-year-old Mengqi Ji, whom he reported missing in October 2019. Her remains were found in March at a park near Columbia, Missouri. Prosecutors rested their case on Monday, after presenting a week of evidence that detailed the couple’s troubled and deteriorating relationship before her death. Ji moved from China to Missouri to study at the University of Missouri and stayed after marrying Elledge in 2017. The couple had a young daughter. Elledge initially told investigators that he and his wife argued at their apartment on Oct. 9, 2019, and he discovered she was missing when he woke up the next day. During opening statements last week, Elledge’s attorney, Scott Rosenblum, acknowledged that …