The internet is your friend :-). Looks like officer choice with limits on caliber.
"TenBrink, who has been with APD for 31 years, said he is one of only two people on the force who carry the .41. His weapon of choice is a Smith and Wesson .41 Magnum, model 58.
On Jan. 1, 1990, a department rule was changed and new recruits were no longer given the option of a .357 or a .41 magnum, TenBrink said. The standard issue today is either a 9 mm or a .45 magnum."
Amarillo.com | Local News: Officers' firearms aren't all the same 04/16/07
BTW I am sure the ".45 magnum" is reporter error.
m.