The cold-hearted killers of the Karims, pictured, stole the video footage which showed them in the shop, just moments after committing the frenzied double-stabbing.

The shock discovery was made as the relatives of Mohammed 'Tony' Karim and his wife Bilquis did a stock take of the store to see what had been stolen.

Police believe the footage, which they presume shows the killers entering the shop, was stolen at the same time the slayings took place.

Meanwhile, appeals in Urdu, Bengali and Gujerati have been placed around the town appealing for information from the Asian community and an appeal has been launched on the Internet at www.lancashire.police.uk.

The Karims' last-known movements were:

8am: The last confirmed sighting as they dropped their grandchildren off at a Blackburn primary school.

9am: Locals say the Karims opened their Church Street shop as usual. Police believe they conducted a brisk trade during the day before the attack. At some point, neighbours say they went for lunch.

Early Afternoon: A witness said he saw a man with a skinhead haircut behaving strangely outside the shop.

Police are keen to talk to any customers, passers-by or bus passengers who were in the Church Street area from noon onwards.

3.30pm: The Karims were due to close the Preston shop and return to Blackburn.

The couple's sons, Shabir and Shafiq, were informed that the grandchildren had not been collected from school and they rushed to the Church Street shop.

They broke into the premises, using a hammer borrowed from a neighbour, and found their parents' bodies in a blood-soaked room at the rear of the shop. An ambulance arrives minutes later.

5pm: Police called to the scene after receiving a telephone call from the shop.

Converted for the new archive on 14 July 2000. Some images and formatting may have been lost in the conversion.