16-year-old Grace Heaslip was reported missing by police on the afternoon of April 7.
Taking to Twitter, the force said: "Grace HEASLIP age 16yrs #missing from #Isleworth area, we really need your assistance to find Grace.
"Call 101 quote ref 17MIS014773.
Anyone with information relating to the whereabouts of the teenager should call police on 101, stating 17MIS014773 as a reference.
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