Clues on bomb blast lead nowhere

Last week's bomb blast in Antwerp's Jewish quarter - caused by 200 pounds of TNT packed in a van parked near a synagogue - has left this city's Jewish population sadly shaken and wondering when the next attack will come.

The midmorning blast in the city's densely populated diamond district - a three-block section near the central railway station where 7,000 Jews earn their living - followed by less than two months a grenade-and-pistol offensive on a synagogue in Vienna which left two dead and 17 injured.

Three Arabs were detained. A year ago, four were killed and 30 hurt in a bomb attack outside a synagogue on Rue Copernic in Paris.

Finding links between the crimes has left investigators frustrated. Predictably, Israeli officials have blamed Palestinian agents. Following the Antwerp attack, the Israeli embassy in Brussels said that ''blind Palestinian terrorism strikes at Jews wherever they are.'' The Palestine Liberation Organization, equally predictably, has denied responsibility.

Politicians have been quick to condemn all acts of violence.

For its part, Antwerp's Jewish community has decided against filing a complaint charging the city police with negligence. Instead, the community will increase its own civil vigilance, knowing that - as one Jewish leader put it - the police can only provide ''minimum protection against random violence.''