MADISON, Wis. (AP) – Wisconsin police could not track cellphone locations without a warrant under a bill Gov. Scott Walker has signed into law. The measure Walker signed Wednesday passed the Legislature in February with no opposition. Under the new law, police would have to present details about their investigation when seeking a warrant to track a cellphone. That includes the phone’s owners or whoever is possessing it, the subject of the investigation, a statement of the crime and a statement of probable cause about how tracking the cellphone is related to criminal activity. The bill was among 55 bills Walker signed privately.