Police say Marina Muller was reported missing by her mother on February 27th.
According to investigators, Marina was picked up by her father - 37-year-old David Searles - at 2nd and Spring Garden.
Now, police say, Searles refuses to disclose her location or return Marina to her mother.
The last known address of David Searles was on the 2000 block of North Front Street.
Marina is described as a 7-year-old female standing 4'8" to -4'9" tall weighing 70 lbs. with brown eyes with brown shoulder length hair.
Anyone with information is asked to contact East Detectives Division at 215-686-3243 or 215-686-3244