gabby petito, murdered while on a cross-country adventure with her fiance, brian laundrie. i recently talked to gabby's father, joe, about how he is using his grief for good. >> it's only 10:00 in the morning, but it rained all afternoon yesterday. >> it's the kind of story that dominated the nation's attention. oh my god. 22 year old gabby petito, with her bright blue eyes and blond hair grabbing headlines capturing the media spotlight after being reported missing while on a cross-country camping adventure with her fiance brian laundrie. >> brian stretching during some morning yoga. >> watch the sunset through the lens of social media. things appeared magical. thousands followed their seemingly beautiful adventure of a young couple very much in love. i'm sorry, we've just been fighting this morning, but away from social media, their reality was very different than the life they were posting. can i see your hand? this time captured on police body cam. >> we've been fighting all morning and? >> and he wouldn't let me in the car before. >> why wouldn't he let you in the car? b

gabby petito went missing, then killed by her boyfriend. now we're back now with more of our exclusive investigation into the murder of philadelphia rapper pnb rock. 7-4 in all these police. >> what an embarrassment. >> lapd is on scene at roscoe's in south la, where bullets had been flying just minutes before. no no no no no no. philadelphia rapper pnb rock has been shot three times and is barely holding on, as seen in exclusive footage obtained by true crime news. officers pulled the rapper's distraught fiance back as she appears to reach for an item on the floor, later revealed to be pnb diamond pendant from his necklace. as cops worked the scene, word quickly spreads. pnb rock was dead and the questions begin. >> a murder occurred following a posting on instagram or social media. the posting of that may have led to these individuals learning where he was at. >> social media users immediately start blaming stephanie's geotagged instagram post showing her meal. >> it's my fault. oh my god. >> stephanie blames herself as seen in this polic