Following his first escape in west London, Boakye travelled to an address in Thamesmead, south-east London, where he was located and arrested a day later.
He was taken into police custody and charged on 12 February with escaping lawful custody.
It is understood he was taken to hospital later that evening where he remained until he absconded on 15 February.
A Met Police spokesperson said: “Officers gave chase but could not detain Boakye before he left the building.
“He is 21-years-old, black, of medium height and slim build. He was wearing grey tracksuit bottoms and a dark Nike jacket when he absconded.”
The force urged anyone with information about Boakye’s whereabouts to contact police on 999 quoting CAD4005/15FEB.
The spokesperson added that the force was “currently reviewing this incident to fully understand the events which unfolded” and the Met’s Directorate of Professional Standards had been informed.