HALIFAX -- Kristin Johnston had told friends she wanted to break up with Nicholas Butcher hours before he murdered the popular yoga instructor and tried to kill himself inside her Halifax-area home, a Crown lawyer said Wednesday.

During her opening statement at Butcher's second-degree murder trial, prosecutor Tanya Carter said the 35-year-old man "couldn't be without Kristin Johnston, and killed her."

"The evidence is not complicated. Kristin's life ended in tragedy, and the evidence points to Mr. Butcher committing murder," Carter told the Nova Scotia Supreme Court jury.

Carter said the evidence will show that the pair were dating in March 2016 when Johnston, originally from Montreal, decided to end the relationship.

At the time, Butcher was living with Johnston at her home in Purcells Cove, she said.

Carter said on the evening of March 25, 2016, Johnston was at a bar in the north end of Halifax, spending time with friends.

"She talked about her plans for the future, her difficulty with finding the best way to break up with Mr. Butcher and her desire not to go home that night," said Carter.

Later that evening, the 32-year-old woman went to a friend's house nearby. However, Butcher found out where she was and went there, speaking with Johnston before leaving the house without her, the Crown lawyer said.

"Mr. Butcher went to the same house again a couple of hours later, unhappy with Kristin's continued presence," she said.

Johnston's friend briefly left the apartment, and "that was the last time Kristin was seen alive," Carter said.

When the friend returned, Johnston and Butcher were gone.

The next morning, Butcher called 911 and told the call taker he had killed his girlfriend and tried to kill himself, said Carter.

She said the medical examiner will testify that Johnston had 10 wounds on her neck, and that her death was caused by sharp force.

Butcher, a graduate of Dalhousie University's law school, has pleaded not guilty to second-degree murder.

Johnston, who had opened a Bikram yoga studio in downtown Halifax, had a reputation as a kind and determined businesswoman with what friends described as a "magnetic" personality.