This is exactly what was said in the warrant:
“By determining the dogs (sic) actual weight and sized (sic) utilizing a scale
will assist in the criminal investigation,” Pennsylvania State Police Trooper Ian Keck wrote in the warrant, according to 69 Newes.
Mother of children found mysteriously hanging by dog leash in basement had two hidden cellphones, latest search warrant says
Also, here's a source just in case anyone wanted to see it that the other phones belonging to mom were only found after talking to her surviving son:
In an interview with Snyder’s only other child, a 17-year-old son, troopers were surprised to learn Snyder had multiple phones, the latest warrant notes. Asked if the finding meant that Snyder had failed to turn over the additional cellphones earlier, Berks County District Attorney John Adams said only: “Normally, people only have one cellphone and now we have three.”
Police serve new search warrant, turn up more phones at Berks home where children were found hanged