MILLBRAE, Calif. (KGO) --San Mateo County Sheriff's detectives are using cellphone pings to retrace the steps of a missing man.
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Keith Green, 27, left his wallet and car behind when he left his home in Millbrae on Thursday evening.
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A friend said Green was going to meet with his ex-girlfriend about a child custody issue.
A hiker found Green's cellphone in San Francisco's Golden Gate Park on Friday.
His family and friends are planning to hold a candlelight vigil on Thursday night, hoping for his safe return.
It's set for 7:30 p.m. at Green Hills Park in Millbrae.
Click here for full coverage on the investigation into the death of Millbrae father Keith Green.