Questions About Girl's death

Sadly, they found the body of a 9 year old girl from Bull Head and as I predicted, it was an acquaintance of the family who did the killing.
From the LVRJ: Shortly before 8-year-old Isabella Grogan-Cannella was reported missing Tuesday, she was playing hide-and-seek with the family friend now charged in her disappearance and death.
Bullhead City police booked Justin James Rector, 26, into the Kingman jail early Thursday morning on first-degree murder and kidnapping charges, according to Mohave County Sheriff’s Office spokeswoman Trish Carter. An extensive search for the girl culminated Wednesday in the discovery of a body less than a mile from her home. The Mohave County coroner confirmed Thursday that the body was Isabella....
Rector had been staying with Isabella’s family for a few days, Williamson said. Isabella, who was called “Bella,” was put to bed late Monday night and discovered missing from her home about 1 a.m. Tuesday.
Isabella’s 10-year-old sister told police that she, Isabella and Rector were playing hide-and-seek late Monday night while the mother, Tania Grogan, was at Wal-Mart.
The sister went into a bedroom to find that Bella and Rector were no longer there, called Grogan and alerted an adult who was upstairs at the home. Grogan returned home and, after an unsuccessful search, called police at 1:18 a.m.
More than 100 personnel, assisted by police dogs and a helicopter, searched for the girl, who had apparently vanished without a trace. A break in the investigation came late Wednesday afternoon when police announced the discovery of a body. Shoe prints at the scene were a match for Rector, Williamson said.
“Inside the shallow grave detectives found the body of Isabella, who was still dressed with the same shirt as the night she disappeared,” a police affidavit said. “Isabella was also found with no shorts or underwear.”  http://www.reviewjournal.com/news/nevada/man-charged-killing-8-year-old-arizona-girl
It has been reported by different media sources that this thug texted the family saying he had the little girl and asked them what they were going to do about it.
If this is true, why wasn't there an Amber report sent out, throughout northern Arizona and southern Nevada?
But it is possible the family never relayed the messages to the cops and if they didn't give the cops this info, then they are just as guilty as the thug who killed the girl.
Further, the thug has a long criminal history, so why did the family allow him to stay with them?
To me, it is clear that the family- mom and boyfriend, are least partially responsible for the poor little girl's death.
Finally, kudos to Wal-Mart and their security team for catching the guy shoplifting and calling the cops.  This case may not have been quickly solved if not for the employees at Wal-Mart.