The police raided the underground parking lot where suspects were reported to deal drugs.

deal 在这里是动词，意思是"进行交易、买卖"。 drugs 是 drug 的复数形式，指"毒品、药物"。 deal drugs 是一个固定搭配，意思是"进行毒品交易"，指非法买卖毒品的行为。