The time of death of Chris was determined to be between 10:30 - 11:00. A fact that would have been very hard, if not impossible, to determine after the body had been frozen and dumped in a lake.
When Ben looks up the message's "IP" he's looking at email headers, SMS does not have email headers.
When Ben looks up the message's "IP" he's looking at a screen of Linux's "ifconfig" that will show him his own IP, not the IP of the SMS.
After Chris has been dead for several days - with some of that time being spent in a swimming pool, followed by time in a freezer, followed by time in a lake - the pathologists manage to pinpoint his time of death to a particular 30 minute window. (Which means that Jojo's confession must be false.) This level of accuracy is totally unbelievable.
On returning to their house after Jojo confessed he was the one who killed Chris, Lauren demands to know, in the presence of police officers, whether Sia, or her friends, had anything to do with the death. Contradicting the confession in this way in the presence of the police does not seem a wise idea.
No blood toxicology report.