. >> with two young kids of his own, this case had already hit rick arnold hard. on the spot, he made a promise to erica's grandmother. you said we're going to find who did this? >> yes. >> that's a lot to promise somebody, isn't it? >> yes, it is. >>> coming up, a glimmer of hope from baby erica. >> i was rubbing her hand and she opened her eyes. >> when "dateline" continues. the only fda-approved once-daily 3-in-1 copd treatment. ♪ trelegy ♪ the power of 1,2,3 ♪ trelegy ♪ 1,2,3 ♪ trelegy woman: with trelegy and the power of 1, 2, 3, i'm breathing better. trelegy works three ways to open airways, keep them open and reduce inflammation, for 24 hours of better breathing. trelegy won't replace a rescue inhaler for sudden breathing problems. trelegy is not for asthma. tell your doctor if you have a heart condition or high blood pressure before taking it. do not take trelegy more than prescribed. trelegy may increase your risk of thrush, pneumonia, and osteoporosis. call your doctor if worsened breathing, chest pain, mouth or tongue swelling, problems urinating, visio