O'Connor Cell Phone Forensics uses the call detail records of mobile phone providers to plot the approximate location of a cell phone as inidicated by the call detail records and the locations of the provider's towers. This evidence can be used in both criminal and civil cases to affirm or deny alibii locations or to indicate a change in call activity such as the number of calls placed between two parties over a given period of time. The principal of this company, Terrence P. O'Connor, is an associate professor in the department of Electrical and Computer Engineering Technology at Purdue University. He has testified in numerous murder cases where evidence from call detail records is often used.