that day kiya died, i feel i died also. sometimes i feel i'm just walking around her, i'm just existing, i'm just walking around here, just because i'm breathing. but it hurts every day. it hurts to the core. >> watch more "faultlines" on demand or visit aljazeera.com/faultlines. >> looking for a small .357 or .38 caliber revolver, preferably made by ruger. oh here it is. this is the weapon that peter used to kill zakiya lawson. handguns are the most common weapon used in domestic violence homicides. >> this is armslist, it's the largest online gun site in the country. >> i'm looking for a cheap handgun for around .150 and $250. he's laying the money on the bed. this is completely unregulated. anyone can buy from a private party here without going through a background check. private sales can be completely anonymous -- no id, no background check no records. >> critics call this the "private sale" loophole, an estimated 40 percent of gun sales that are largely invisible. >> we'd been told that south carolina's weak gun laws