Call Detail Records Find Missing Person in San Mateo County, CA

On Wednesday, November 21, 2018, around 5 pm, a 70-year-old man left from his home in Cupertino, CA for a drive to the mountains looking for a place to go on a walk, which was quite common.  Two hours after leaving his home he called his family and told them that he was lost somewhere in Woodside, CA.  After not hearing from him again and repeated calls to his cell phone going to his voicemail, the family used the “Find my iPhone/iWatch” app which showed geo-locations in two separate areas in Woodside, CA.  The family drove to those locations and did not find their loved one.  Fearing the worst, at 9:45 pm, the family contacted the San Mateo County (CA) Sheriff’s Office to report him missing and seek law enforcement help.

The San Mateo County 9-1-1 communications center started pinging the man’s cell phone through Verizon to try to get a location of his whereabouts.  Investigators also attempted to use the “Find my iPhone/iWatch” app which showed the same geo-locations the family viewed, however, the locations were not changing, leading investigators to believe he may have been involved in a traffic accident or something worse.   The pings being received from Verizon also showed consistent geo-locations throughout the night and they too were not moving.  Patrol deputies, with the assistance of their fixed-wing aircraft, searched throughout the night into the early morning hours using the pings and apps but were unable to locate the missing man.

The next morning on November 22nd (Thanksgiving), investigators reached out to Hawk Analytics (exigent support) for assistance.  Hawk Analytics is a software company that provides assistance to public safety agencies specific to analyzing and mapping cell service provider call detail records (CDR) involving investigations such as critical missing persons cases or violent crimes.

Due to the exigent nature of this incident, a critical response team from Hawk Analytics was activated to analyze these records to see if a specific search area could be identified.  The Investigators, along with the Hawk team, knew the clock was ticking and if a traffic accident did occur, the missing man could still be alive.

Generated using CellHawk

Exigent requests were made to the man’s cell phone provider who promptly provided CDRs and specialized location records.  These records contained historical cell activity such as phone calls, text messages, and data connection usage events.  These records provide details such as which cell towers and sectors (antennas) were being used with a date and time stamp.  The specialized location records, known as RTT, contained even more detailed information such as distance from the tower and an estimated location of the handset.

By analyzing the records in Hawk Analytics CDR mapping software CellHawk, the Hawk team was able to determine the phone was most likely in the immediate area of State Road 84 (La Honda Road) and east of State Road 35 (Skyline Blvd.) in a mountainous, rural area of San Mateo County, CA.  When compared to the “Find my iPhone/iWatch” geo-locations, this new location derived from the CDRs was within one mile.

A revised search plan was put into motion focusing efforts on La Honda Road, east of Skyline Blvd., and within minutes patrol deputies located a damaged tree along La Honda Road.  When they looked down the embankment, they saw the vehicle overturned on its roof.  Deputies quickly descended down the embankment and found the missing man trapped in his vehicle, alive and conscious.  A lengthy extrication operation ensued and eventually the man was rescued from the wreck and transported to the hospital and treated for his injuries.

Thank you card from family

It’s not only the technology that is impressive, but also the way the company jumped into action at night and on a holiday to help us rescue the victim,” said Assistant Sheriff Greg Rothaus. “Failure was not an option in this case and CellHawk stayed with us through the night and up until we found our guy.

San Mateo County PIO:

If you would like more information about this incident, please contact San Mateo County (CA) Sheriff’s Office PIO Detective Rosemerry Blankswade at 650-363-4800 or via email at

Hawk Analytics, Inc. PIO:

If you would like more information about Hawk Analytics and/or CellHawk, please contact Nick Barker at 469-373-HAWK (4295) ext. 705 or via email at


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