There's been so many questions of cell phones and pings on here. This article gives a really good novice explanation.
What Your Cell Phone Can’t Tell the Police
The answer is ... Not likely in this case.
You would have to have at least one or more of these things:
1. Have the perps phone in LE possession
2. Have a suspect to issue a warrant to their carrier for records
3. Perp would have had to been allowing location services on a GPS capable phone with them. Registered to them.
4. #3 .... PLUS the perp placed a phone call or texted while on Closs property
They cannot just pull a log that lists everyone in that area in any given time frame. As we have no perp phone and no real suspects ... #3&4 together would be the most likely way to nail down someone as having been there during the commission of the crime.
If premeditated, I don't think most people about to commit a double homicide and kidnapping are going to have their location services on and make a call or text in the middle of it. It has happened that someone did so nearby before or after the crime but I think LE would have that information and been acting on it already if it showed anything.