Sussex Police are urgently seeking to locate Eder who has been reported missing from Brighton.
The 13-year-old was last seen in the city at about 11.30am on Saturday, June 24.
He also has links to Eastbourne.
Eder is described as a skinny boy, 5'8, with brown hair and brown eyes.
He was last seen wearing a dark-coloured tracksuit and black trainers.
Anyone who sees him or knows his whereabouts should call 999 immediately and quote serial 651 of 27/06.