The guy(主语) we are looking at(状语,修饰主语) looks like(谓语) a criminal for(和search搭配的介词) who(应该用whom,介词后面只能用宾格的) the policemen are searching a long time.其他的没问题
The guy we are looking at looks like a criminal for (whom ——宾格)the policemen are searching a long time.
The guy we are looking at looks like a criminal whom the police are searching for a long time.
把who改成whom; searching后面加for
少了一个for吧