A Muslim girl of 13 and her father have been arrested on suspicion of murdering her boyfriend
Sumon Miah, 21, was beaten to death with a table leg when he went to visit the youngster at her home.
All four members of the girl's family were in police custody over his death.
Neighbours said that the schoolgirl's parents had been 'deeply unhappy' their daughter had started a relationship with a man eight years her senior.
A family friend said: "You can imagine how upset the girl's mother and father were to know that their daughter was seeing a man of 21.
"Although the relationship was in its very early stages, they wanted it to stop as soon as possible."
On the day of the murder, the girl's family made several calls to the police - telling 999 staff of their anger that Mr Miah was planning to visit their home in Walthamstow, East London.
But by the time police arrived, Mr Miah, from Bow, East London, was on the brink of death after suffering severe head injuries.
He later died in Whipps Cross hospital and Scotland Yard detectives have now arrested the 13-year-old's entire family.
While the youngster and her father have been quizzed over the murder, her brother, also 13, and 41-year-old mother have been held over allegations that they conspired to pervert the course of justice.
The girl is also being questioned over conspiring to pervert the course of justice.
The Muslim family, who are originally from Bangladesh, called police about their concerns over Mr Miah on October 8.
But officer failed to respond to a series of calls.
They arrived just after 11am and found Mr Miah slumped on the floor in a pool of blood after being beaten with the table leg.
Family held over boyfriend death
UK: Muslim Family Arrested After Man's Killing