Newbie question, Workers & Peasants Militsiya blue star?

[Koba64]

Hello folks, I'm more of a modeller than a collector. I am making an early Militsiya figure and need to research the correct cap badges for the period before i cast the results in pewter.

I'm hoping that someone can help me out with maybe a picture or a decent description of the blue star cap badge that officially replaced the shield-shaped red badge of the Militsiya in 1931.
I am reading the Bekesi & Torok 'KBG and Soviet security uniforms & militaria' and this is mentioned on page 15.

As well as the blue star I would greatly appreciate a look at the original red shield badge as well because there are no close ups of this in the book.

Best regards,
Mike