MY OPINION ONLY
All of us can theorize and imagine and speculate. In so doing we weight the extremely limited, incomplete, and often questionable evidence we have available, filtered through the prism of our experiences and biases, and we come up with "gut" conclusions that are worth little.
Unlike some here, I have little confidence in the local prosecutors. Not because I think they are incompetent, but because this is going to be a very difficult case to successfully prosecute. Despite what some have said there is little to no reason to delay an arrest if there is sufficient evidence to warrant a charge. The prosecution does not need to have their entire case complete before filing charges, they just need enough to convince a judge that an arrest is warranted. If they had that they would go for it, if for no other reason than that it might serve to frighten people into talking and it gets a potential killer off the streets. As an added bonus, it's their JOB, and what the people of their community expect from them.
Because there were multiple people with access to the girl, the prosecution needs something that ties at least one of them to the body, the murder, or both -- and this is assuming that they have evidence that the girl was actually murdered. While the media is reporting that the girl's body was wrapped in a blanket, no one connected with the investigation has publicly said anything of the sort. To date we do not know how the girl died and we do not know the condition of her body when found.
All we have is the family, and their behavior, but that's not a lot to go on -- and from the actual evidence (assuming it is accurate) there is no reason to believe that ANY of them were involved in this girl's death. We have the step father with a history of mental illness and a VERY minor violent incident in his past -- but his activities on the day the girl was reported missing, while insensitive and (as it turns out) wildly incorrect, help dismiss him as a suspect. He wasn't out there playing the loving father, wailing and rending his clothes and leading the search, he was the guy posting messages to cam-*advertiser censored* on FB. We can, of course, construct or imagine a scenario involving the step-dad which ends in murder, but there is no evidence of this yet.
We have the ex-con older "brother" who Celina seemed to adore and who seemed to really like her in return. Some have suggested that their relationship was perhaps inappropriate (they do, after all, hug each other quite a lot in pictures), and that he was grooming her to molest her. This could be correct, but it conveniently overlooks a critical point. Even if he had an illegal and inapprorpriate attraction to his "sister" and spent the year or longer that he lived with her carefully grooming her to reciprocate his feelings, there is NO reason to believe that his desires included or might lead to murder. After all, they like each other, and from Celina's expressions in the pictures we have seen she feels the same and might even have something of a crush on the guy. This doesn't seem like the kind of relationship that regularly leads to deliberate violence or murder, and the statistics bear this out. We can, of course, construct or imagine a scenario which ends in murder, but there is no evidence of this yet.
And then there is mom. Mom's behavior on the day that she was discovered missing is reportedly odd. Again, reportedly. We really don't know. The source for this information is certainly credible, they are not lying, but that does not mean that what they think they saw or what they believed, was an accurate observation. Mom seems to be genuinely crushed, she seems to have really loved her daughter, and there is NO evidence that this impression is inaccurate. We can, of course, construct or imagine a scenario involving mom which ends in murder, but there is no evidence of this yet.
We know, statistically, that in approximately 90% of all cases of this type, with children under age 12, the perpetrator was someone who was close to the girl -- usually someone in her own family. We know, statistically, that the crime likely took place in a residence, and it is statistically (and logically) likely that the crime (assuming there was one) took place in the family home. But statistics can only go so far, they serve as a guide to help direct an investigation rather than a map to the killer.
Hopefully the DA's office has or discovers something solid. I would like to see this girl's killer, assuming it was murder, receive the justice they deserve.