Police officers investigating the murder of British schoolgirl Mary-Ann Leneghan today arrested a fifth suspect in London.
Earlier police said up to 60 police officers have joined a round-the-clock hunt for those who killed and sexually assaulted the teenager and severely injured her friend.
Mary-Ann Leneghan(16), whose father is from Co Mayo, was found dead on Saturday morning in a park in Reading after suffering a stab wound to the neck; her unnamed 18-year-old companion was left with a gunshot wound and is still in hospital.
The injured teen has been helping police who believe the two girls were targeted deliberately.
Four other men have so far been arrested and released on bail by police.
Thames Valley Police, who have offered a £10,000 reward for help in catching the killers, said up to 60 police officers were now working on the case.
They said the two victims had been seen in a maroon or burgundy car with loud music coming from it and around six men inside before the attack.
The two girls and the men are also understood to have spent several hours in a Reading guest house.
The 18-year-old raised the alarm just after 5am on Saturday and Ms Leneghan's body was found shortly afterwards.