Information on offenses and offenders was obtained through the West Yorkshire Police Criminal Information System. The first group of 11 offenders considered was selected by the Major Crime Unit of the West Yorkshire Police as being the most prolific group of offenders who committed burglary by deception. Data showed that the most prolific offenders were also those who repeated crimes on the same street, sometimes returning to the same address. There were no statistically reliable differences between offenders in their tendency to choose houses close to one another. The close proximity of victimized houses was a general characteristic of this group of offenders rather than specific to a few of them. A second study involved an analysis of crimes committed during a 3-month period (May to July 1993) in one area of West Yorkshire. Having identified all the crimes reported during this period, all individuals who had come to police notice in connection with one or more of these crimes were identified. They were then sorted by the "nominal" identifier, and the first and last 30 of these numbers chosen for further analysis. Offenders were categorized by their total number of offenses that were cleared. A relationship was found between the number of offenses for which a perpetrator was known to be responsible and the proportion of the offenses that were repeated against the same target. Repeat offending against the same target was a characteristic of prolific offenders among those with criminal careers that extended over a considerable period. Among the implications of these findings was that repeat crimes should be given priority for investigation, since they were most likely to have been committed by prolific offenders. 6 tables, 15 references, and 5 notes