Gmail doesn't search for message in Spam or Trash unless you tell it to. Here's how you can include spam and trash in your search results:
- Sign in to Gmail.
- Click Show search options at the top of any Gmail page.
- Select Mail & Spam & Trash from the Search: drop-down menu.
- Enter all other criteria for your search in the appropriate fields.
- Click Search Mail.
Learn more about Gmail Search.