That's what the cops tell judges - and sometimes use that inaccurate assertion to lock up innocent people for a decade...

https://www.newyorker.com/news/news-desk/what-your-cell-phon...

"On May 28th, Lisa Marie Roberts, of Portland, Oregon, was released from prison after serving nine and a half years for a murder she didn’t commit. A key piece of overturned evidence was cell-phone records that allegedly put her at the scene."

If it's as accurate and straight forward as law enforcement tell us - how did _that_ happen?