kayden killed by her own biological father, jeffrey mancuso in a murder/suicide. just one month after her murder, kayden's mom and stepdad, cassie and brian sherlock, speaking out against a family court system they say failed kayden by not properly taking into account jeffrey's violent history and what kathy says were her repeated cries for help. do you feel like your daughter's death was preventible? >> absolutely, oh my god, absolutely. >> 100%. >> every single thing that could have stopped it at some point, it just didn't. >> reporter: with three beautiful kids and a new puppy, the sherlocks thought life couldn't get any better. but there was somebody else in the picture. kayden's biological father, jeffrey mancuso, whom kathy met one summer on the jersey shore. >> it was a fling? >> yeah, basically. >> reporter: they mefr married but they moved in together when kathy found out she was pregnant. >> i thought that's what i had to do, to try for kayden to give her two parents. >> reporter: despite the chill between mom and dad, sister alison says the father/daugh