The jury delivered their verdict to B.C. Supreme Court Justice Geoff Barrow on Tuesday night, after only six hours of deliberations.
Wiens was charged after police found the body of 55-year-old Kalmring in the couple's Penticton home in 2011. Police say she had been shot in the face.
During the trial, Wiens sat quietly, staring straight ahead, as a crown lawyer told the jury Wiens deliberately shot Kalmring during a heated argument.
The crown argued the former mountie then moved her body, placing a knife in her hand to make the killing look like self-defence.
Wiens pleaded not guilty, his lawyer insisting Wiens did shoot Kalmring in self-defence. He painted a picture of a woman, hysterical over the fear her husband was going to leave her.
The defence said Kalmring wanted to kill herself, but only after she had ended Wiens' life with the knife.
Wiens spent 20 years with the RCMP in Summerland.
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