The police warned the public to be cautious of phone calls that promise quick riches through scamming.

scamming 是动词 scam 的现在分词形式。scam 的意思是"诈骗、欺诈"，指通过欺骗手段获取他人钱财的行为。scamming 在这里指"通过诈骗手段"的行为。