Partial name user search


Hi, I’ve ran into the following issue when using REST API.

Let’s say I’m searching for Bruno Mars’ account. So this query “q=Bruno” actually returns his account as the top result. With both REST API and Twitter Search:

But if the query is “q=Bruno+M” (or even “Bruno Mar”!!) the results are completely different and don’t include the user I’m looking for:

However I noticed that twitter’s autocomplete/typeahead search results (just type “Bruno M” into the search field on work differently and return this user, this is the URL calls:

But if I click on the search icon, then the results don’t include Bruno Mars like I said above. Same with REST API.

How do I do typeahead type search using REST API?