Police are also appealing to the public....
Mohanad Abdullaahi Goobe was just 15 years old....
He remains in custody for questioning....
Police are now appealing for information....
Investigations are said to continue 'outside of public view'....
A 59-year-old man has been arrested on suspicion of murder....
He was found guilty of manslaughter....
Four arrests have now been made in total....
A murder investigation is now underway...
