Prison staff have launched an urgent investigation after a teenager taunted the mother of a schoolboy he murdered in rap videos from his cell.
Marques Walker, now 17, used a smuggled mobile phone to film himself rapping, dancing and smoking at Feltham Young Offender Institution.
He was on remand at the time after stabbing Jermaine Cools, 14, seven times with a zombie knife in Croydon, South London in November 2021.
