San Jose police are asking for the public's help in breaking up a ring of purse snatchers who are targeting Asian women.

Detectives say two or three separate gangs they're calling "The Rippers" have been stealing the purses of women as they walk through parking lots.

Police suspect the ring has committed 21 robberies since November, some of them in crowded and well-lit parking lots.

Four arrests have been made so far, but the attacks are continuing.

In the most recent incident, a woman was robbed of her purse as she walked through a Costco parking lot Tuesday evening.

Police say in all but a single case, the victims of the attacks have been Asian.