. >> four years ago patrick mcstay lost everything he loved. four years ago, his son joseph, daughter-in-law summer and their two little boys four-year-old gianni and three-year-old joseph junior vanished. >> i don't think they knew what was coming, i really don't. >> how did you find out that they had gone missing? >> friday i tried calling him, couldn't reach him, sunday couldn't reach him. now i'm getting worried. >> worried because patrick says he rarely went a day without hearing from his son. >> every time i talked to him, the last words out of my mouth before we hang up the phone is i love you, son. >> if he was in trouble and had the ability to reach out to you, do you think he would have called you? don't you think he would have? >> absolutely. >> this case is unique. i've never seen anything like it. >> freelance investigative journalist stef watts followed from the beginning. >> they literally disappeared and nobody noticed for days. >> thursday, february 4th, 2010 began as an ordinary day in the mcstay home. >> that morning i spoke

then investigators did something patrick mcstay finds unbelievable. >> they don't put any tape on it,cene tape, any notices on the door. nothing. they lock the house back up and they leave to get warrants. >> it doesn't make any sense to me. you've got a family that's missing for a week and they are still not going to call it a crime scene? >> reporter: it took san diego investigators three days to obtain the warrants they needed to complete a full search of the home. but during those three days, the mcstay's home remained unsealed, which allowed joseph's brother, mother, and friend access in and out of the house. >> i wouldn't go in there unless i called, you know, the sheriffs department and they said i could, so i had permission. i cleaned up the kitchen because it was disgusting and the trash can from diapers sitting there all that time, you know, it was terrible, terrible smells. >> she was cleaning. we were looking for bank statements. i mean, i think she was just reaching for evidence. >> it was a crime scene? >> no, it was not deemed a crime scene because there was no sign of

. >> four years ago, patrick mcstay lost everything he loved.is son joseph, daughter-in-law summer, and their two little boys four-year-old giana and joseph jr. vanished. >> i don't think they knew what was coming. i really don't. >> how did you find out that they had gone missing? >> friday i tried calling him. couldn't get him. sunday i tried calling and couldn't reach him. now i'm getting worried. >> worried since patrick says he rarely went a day without a phone call from his son. >> every time i talk to him, the last words out of my mouth before we hang up the phone is i love you, son. >> if he was in trouble and had the ability to reach out to you, do you think he would have called you? don't you think he would have? >> absolutely. >> this case is unique. i've never seen anything like it. >> steph watts. >> they literally disappeared for days and nobody noticed. >> it began as an ordinary day in the mcstay home. >> that morning i spoke to him on the phone. >> but he didn't let off anything was wrong. >> no, everything is fine. >> he was pl

but still patrick mcstay, joseph's father, the husband in this case said they would never go to mexicohe said that his daughter-in-law didn't even like mexico but still investigators early on remained focused on the packet they went there, never imagining their bodies would be found more than 100 miles north of their home. >> who is handling the investigation now? do they feel dlae they're closer to solving thissing >> they have a brand-new detective on the case that has gone out to the desert and looked at the shallow graves going through thousands of page work. this was really a problem because critical time was lost here. the house where they disappeared from, their home wasn't searched with a warrant by san diego who was originally handling this till 15 days after this family disappeared. in that time, brook, other family members came and went, came in and out of the home. who knows what evidence could have been lost there. >> randi kaye, we will be watching. it's a one-hour special documentary called "buried secrets, who murdered the mcstay family," at 9:00 eastern right here on c