and there were good reasons, he felt, to take a close look at michael peterson. asons, he says, that had nothing to do with peterson's very public criticism of the police. >> he may have had some issues with -- with the p.d. you know, i don't -- my perception of that is that i don't -- i don't pay much attention to -- i -- i don't really like politics anyway. so therefore, it didn't affect me one way or the other. >> reporter: the detective wanted to know more about what was going on inside the peterson home. >> in addition to the forensic evidence you're gathering, you got to ask this question, "what's going on in this marriage?" huh? >> right. >> that's a big part of your investigation? >> right. >> reporter: detectives pulled aside kathleen's sister candace to ask if she'd noticed any trouble in her sister's marriage. >> the police took me in a police van to interview me privately. >> reporter: in her grief, candace was hesitant to say anything bad about her now widowed brother-in-law. she'd always liked him. >> he was a fun person to sit and chat with across a