盗窃案 is the headline/police-blotter word for a theft incident, formed by
盗窃 ('to steal') +
案 ('case'). The natural measure word is
起 (qǐ), used for 'incidents' (
一起车祸 'a traffic accident',
一起谋杀案 'a murder case'). Pair with
重大 (major),
系列 (serial), or
入室 (home invasion) to specialize.