The crime rate, already high here, has soared in recent months, with murder and car theft at the top of the list. The murder rate of some 21 a day is twice the rate of last year; these days a car is stolen every ten minutes. Such crime in Caracas used to be confined to the slums ringing the city, but it has now spread to upscale areas. A presidential election is scheduled for May 28 and could be marred by unrest.