Crime: Police baffled as Mardi Gra strikes again

On Saturday the Mardi Gra bomber struck again leaving a parcel outside a branch of Sainsbury. After a dormant 11 months, there has now been a pattern of similar attacks in recent weeks. Kate Watson-Smyth tries to uncover the man behind the campaign.

Anti-terrorist police hunting the Mardi Gra bomber are intensifying their search as fears grow that he is planning to target supermarkets in the pre-Christmas shopping rush.

Covert operations at branches of the Sainsbury chain are expected to be extended in an effort to catch the bomber before he strikes again. Detectives fear he may use the added cover of the Christmas rush to cause chaos.

On Saturday, a shopper escaped unhurt after accidentally taking home a live device left in a plastic carrier bag at the West Ealing branch. Police believe the bomb had been left at a bus-stop in a Sainsbury carrier bag, where the 73-year-old woman inadvertently picked it up along with her own shopping.

The device was made up of what police described as an "improvised shotgun" with the words Mardi Gra on it. It was about 20cm long and contained a timer, a spring, a copper tube and a shotgun cartridge.

No one knows whether he is a man with a grudge or simply someone who enjoys pitting his wits against the police. Over the past three years, and almost 30 incidents, detectives have amassed large amounts of technical information about the bombs he builds - particularly those that failed to go off - but gathering information about the man himself is proving difficult.

Unlike other investigations into terrorist activities, the Mardi Gra inquiry is being hampered because there is no network of informants to draw upon as the bomber is thought to be a loner who acts on his own.

Since 1994 when the first package was left outside a branch of Barclays Bank, there have been periods of intense activity followed by long periods of hibernation.

But the silence of the past 11 months is over. On 15 November, the start of the latest series of attacks, he planted a cassette, containing a 12- bore shotgun cartridge wired to a spring- loaded trigger, in a bag of groceries at a branch of Sainsbury at Ruislip. Two other devices exploded on the same day, one at the entrance of a branch in Ealing, the other in Greenford.

On 25 November, an exploded device was found near a branch of the supermarket in Chislehurst, Kent and another was taken into the customer services department of the Lea Green store and was made safe.

Police believe the Mardi Gra bomber may have been inspired by the Unabomber, who is currently on trial in America. Once one of the world's leading mathematicians Theodore J Kaczynski, became obsessed with the growth of technology and waged an 18-year campaign on the people who worked in these industries.

trail of terror

1 6 December 1994: Barclays Bank, Hampstead, north London

2 6 December, 1994: Barclays Bank, Ladbroke Grove, west London

3 6 December 1994: Barclays Bank, Hammersmith, west London

4 6 December 1994: Barclays Bank, Earls Court, west London

5 6 December 1994: Barclays Bank, Kensington, London

6 6 December 1994: Barclays Bank, Paddington

7 19 May 1995: Private address in Cambridge

8 9 June 1995: Pub in Chiswick, west London

9 10 June 1995: Camera shop in Dymchurch, Kent

10 20 June 1995: Barclaycard, Northampton

11 5 July 1995: Barclays Bank in Berkhampstead, Hertfordshire

12 14 July 1995: Private address, in Amersham, Buckinghamshire

13 15 July 1995: Private address, Richmond, Surrey

14 19 August 1995: Private address in Welling, Kent

15 12 September 1995: Office, Whitton, Middlesex

16 27 September 1995: Office in Woolwich, south-east London

17 2 October 1995: Rymans, Chiswick, west London

18 24 October 1995: Phone box in Welling, Kent

19 20 November 1995: Telephone box in Eltham, south-east London

20 12 December 1995: Private address in Southall, west London

21 19 December , 1995: Telephone box in Acton, west London

22 30 January 1996: Barclays Bank in Ealing, west London

23 5 February 1996: Barclays Bank in Eltham, south-east London

24 20 April 1996: Barclays Bank in Ealing

25 15 November 1997: Sainsbury in Ruislip, Middlesex

26 15 November 1997: Sainsbury in Ealing

27 15 November 1997: Sainsbury in Greenford, Middlesex

28 18 November 1997: Sainsbury, Chislehurst, Kent

29 18 November 1997: Sainsbury in Lee Green, south-east London

30 6 December 1997: Sainsbury in Ealing.