MacDonald’s high school sweetheart and the family of both parties were interviewed. Frank Myatt told the Evening Express that he had hoped to marry Lillian. He last saw her two days before her murder. Alexander MacDonald had unknowingly brushed past his daughter’s killer on the night of July 13, while visiting the police station in search of answers about his missing child. He was questioned by an Evening Express reporter on July 14, expressing his regret in not seizing the moment to “[tear] him to pieces”. Mrs. Mitchell was also consulted, expressing her disbelief in her son’s crime.
On August 6, Mitchell traveled to the State Hospital for a mental examination. He was judged to be sane and returned to his Portland cell on September 25. That same day, his case opened. Only seven minutes into the trial, Mitchell pled guilty. He was sentenced to life in prison.