LANSING, Mich. - An arson investigator's "negative corpus" approach to determining a fire's cause rendered his opinion inadmissible; however, the erroneous admission was harmless given the other evidence, a Michigan Court of Appeals panel held April 1 in affirming a woman's arson and insurance fraud convictions (People of the State of Michigan v. Audrey Devonne Pruitt, No. 313065, Mich. App.; 2014 Mich. App. LEXIS 584).