Officers have been scouring airport security videos for footage of someone heavily bloodstained or dragging a heavy case.

The BBC's Liz MacKean: "Police have questioned passengers"

A spokesman for the inquiry, which is being led by Detective Chief Inspector Richard Taber, said: "The primary line of inquiry here is to establish who the victim is."

Lightly clothed

The woman was in her 20s, 5ft tall, of medium build and with collar-length auburn or blonde hair, possibly dyed or permed. She had brown eyes and looked Turkish or Moroccan, said Scotland Yard.

She was lightly clothed and wearing a gold chain with circular links but no other jewellery, although her ears were pierced.

The case was on a luggage trolley

The body was found curled up in a locked suitcase in a multi-storey car park at Terminal 3 of the London airport, during a routine patrol by airport security staff.

The black canvas case, 3ft by 2ft by 9ins, was on an unattended luggage trolley on the third floor of the five-storey car park.

The handle and wheels of the suitcase were missing.

"Police examination of the scene is still ongoing ... but it does not appear the attack took place in the car park," said the spokesman.

Open mind

The spokesman said it was too early in the inquiry to say whether police would be liaising with authorities overseas in their bid to discover the woman's identity.

Asked about the possibility of the case being brought into the country, he said: "We will keep an open mind about how the case reached that position in the car park."

Police appealed for help from anyone who saw anything suspicious, such as someone struggling with a heavy suitcase or covered in blood.

Heathrow's Terminal 3 is used for long-haul services to America, the Middle East, Asia, Australia and New Zealand.

The airport serves more than 200 destinations, handling about 1,250 flights a day.

Last year, Heathrow was used by 60 million passengers, making it the busiest international airport in the world.