The questioning extension, granted by Bradford Magistrates' Court, means officers can hold the suspects in custody until Thursday morning before applying for further time, charging or releasing them.

Police described the attack on the teenager as "brutal" and "sustained".

A West Yorkshire Police spokesman added: "Although officers are still working to ascertain the motive, it is not believed to be racial."

West Yorkshire Police officers are still searching the park where the teenager was discovered by 13-year-old James Taylor and his friend, who called 999.

James Taylor has told the BBC how he performed emergency first aid on the 17-year-old in the walled garden of the park after hearing people bragging about "jumping a boy", stamping on his head and leaving him for dead.

The teenager described Amar's face being covering in blood as he trying to help him before paramedics arrived.

He added that he was "scared to walk the streets alone" in Dewsbury because of gangs.

"It's a problem. There are gangs and it's just over turf and over drugs and girls and stuff like that," James said.

Police teams have also been scouring a pond in Crow Nest Park, but senior officers on the investigation would not say whether they were hunting for a murder weapon.

The victim's family is believed to have moved to Dewsbury from London five years ago.

Amar's sister Samreen Aslam said: "This has shattered our family and it won't be the same without him. There will always be a gap when there is a part missing."