GREENSBORO, N.C. — Greensboro Police still want to know how a 20-year-old High Point man ended up at the bottom of a creek just off Wendover Avenue.
Investigators found Nicholas Snead inside his car in Buffalo Creek last Friday. He had been missing since before Christmas.
We asked Greensboro Police Chief John Thompson about the search for Nicholas Snead before his car was found.
Snead's mother previously told WFMY News 2 his phone last showed his location along Holden Road.
Thompson declined to specify whether the ravine along the on-ramp to Wendover Avenue from Holden Road was searched before he was found. He said the location information from Snead's phone was used.
"When a phone pings off of a tower, it's a big geographic area that could be encompassed with that. At the time, officers were provided information about potential locations Mr. Snead was going to. With the ping on the phone, the date and time the phone had pinged. That gave us a very broad area to look," Thompson said.
What is a "ping?"
The chief is talking about when a phone sends a signal to a cell phone tower and the tower sends the signal back to the phone.
The tower keeps a record of which phones ping off of it and when. Tech and cybersecurity expert Ron Pierce of Trinity Solutions Inc. said the problem is, you can't tell exactly where the phone is pinging from.
"However far that tower can reach, that's where that cell phone can be," Pierce said. "Normally a tower can get from 10 to 20 miles of a certain range before another tower picks up."
Law enforcement must talk to the service provider to get access to the records from those towers.
What about GPS?
The second way to locate a phone is through GPS.
Instead of the phone communicating with a cell phone tower, the signal is sent back and forth to a satellite. Apps like Find My iPhone use GPS and it does provide a more specific location.
Pierce said GPS does have its own limitations.
Specifically, a GPS signal will be lost if the phone battery dies or if the phone is damaged.
"If for some reason that phone is not working, those apps are not going to help you get the most accurate information on where that phone is. You're kind of left with a footprint of where the phone was before it disappeared," Pierce said.
Pierce said law enforcement will often combine cell towers and GPS pings to get a better idea of where a missing person is, but it doesn't always work.
"Unfortunately in situations like this, technology where it’s great and can be very helpful, it can also work against you. This may be one of those cases where it just didn’t help," Pierce said.
How did Snead's car get there?
The ravine along the Wendover Avenue on-ramp is deep enough that you cannot see the bottom while driving by. There are also no guardrails between the road and the creek.
WFMY News 2's Grace Holland asked NCDOT whether they could put a guardrail there in the future.
"First our hearts and prayers go out to the family of the young man," NCDOT spokesperson Kelse Edwards said. "Safety is our top priority at NCDOT, we need to gather more information and wait until the official incident report is released by the authorities."