You should look in his pockets for an ID,

[angliholic]

You should look in his pockets for an ID, and I'll call the police.
You should search his pockets for an Id, and I'll call the police.
You should look his pockets for an ID, and I'll call the police.


Do all of the above sound right and mean about the same, espcially the third one? Is in in the first case optional? If not, why not? Thanks.

[riverkid]

You should look in his pockets for an ID, and I'll call the police. Okay
You should search his pockets for an Id, and I'll call the police. Okay
You should look his pockets for an ID, and I'll call the police. Not okay


Do all of the above sound right and mean about the same, especially the third one? Is in in the first case optional? If not, why not? Thanks.

'in' is not optional, A, it's required. I'd say it's necessary because it is meaningful. 'look in' differs from 'look at' or 'look under' or 'look past', or 'look through' .

[angliholic]

Thanks, riverkid, for your clear reply.