Eliminate TIME from COMMENT DISPLAY, but keep date

(In case it is relevant, I am using the Atahualpa theme.)

When comments are displayed, it shows the DATE and TIME of each comment, like this:

Sam Beasley
April 30th, 2009 at 12:42 pm

I would like to continue to display the DATE, but eliminate the display of the TIME.

Where can I find the piece of code that causes it to display date AND time? If I can just find it I should be able to tweak it to suppress the TIME display.

Thanks!
–Mark