reginald potts is under arrest for the murder of nailah franklin. detectives are certain they have their man. but mr. potts? >> i adamantly deny that i was ever there, period. >> reginald potts appears to be insulted they even ask. >> and i can tell you you're lying. >> nailah? he was nowhere near her, he said, the day she vanished. >> i was not in her apartment on the 18th, period. >> or her apartment building? >> or apartment building. >> of course they told him they had evidence. >> distinctive bentley in her [ bleep ] parking garage or building. >> that's it. >> and i can tell you, that's a lie. >> a police frame-up, to which the detectives said -- >> reginald, do you understand about videotapes? there's cameras. >> yes, including nailah's apartment building. and there is reginald, plain as day with nailah. arriving and leaving with her on that very day she disappeared. >> so you knew he was there? >> yes. >> but reginald? doubled down on his denial. >> i am certain that i am nowhere near inside of nailah franklin's apartment building. >> accuse

what happened to nailah franklin?her family continued their desperate search, police honed in on the men in her life. and with a little digging, one of their stories started to unravel. here's keith morrison with more on our story, "smoke and mirrors." >> it's a grassroots effort by family and friends. >> through all the frantic activity, the phone calls, the flyers, the organized looking about, it was a rare quiet time, nine days in. when nailah franklin's sister felt it. >> we had a prayer service at our church, and in my heart i knew. i was like, you know what, she's not coming back. >> and that very night in the 3:00 a.m. hush of calumet city, night patrol officer calvin lucius felt his way past the glittering ear buds his partner saw hanging from a tree to the inky black fringe of forest at the back of a long abandoned parking lot behind a derelict video store. >> i probably got like right around this area and just looked over and the body was there. >> what was that moment like? >> shock. >> you don't know if it

nailah franklin, ambitious, dependable and always on her phone was suddenly radio silent. even with her new love, andre. >> i called her that morning. e-mailed her. called her again. called her again early afternoon. >> and that's when he sent her that all caps e-mail. "are you alive?" and you probably didn't mean it the way it really was. >> no, like you say to someone, are you there? >> at the end of the workday, big sister leah did get a call. not from the nailah, but from nailah's boss. >> he said she had missed a meeting. immediately my spidey senses were high. so of course, i tried to call her. didn't get her. >> so leah called her friends and other siblings. had anyone heard from nailah? >> i didn't speak with her that day, didn't speak with her the day before. >> i said no, i haven't talked to her. >> nicole feared. she called the chicago p.d., filed a missing person's report and then she drove over to nailah's condo, knocked on the door. she got a key. she went in. >> you see her eggs and coffee she had just left there just out. >> something's wrong. >> just like,