SPOKANE, Wash. -

Was he a jealous killer or have Spokane County Sheriff's detectives arrested the wrong man? That's the question a jury will have to decide as Dan Arteaga's murder trial got underway Wednesday.

Arteaga stands accused of killing his girlfriend Kim Schmidt on New Year's Eve 2011.

The prosecutors theorize Arteaga was able to sneak up on Schmidt and shoot her at point blank range because he had taken his small caliber pistol and hid it in a woman's sock as he approached the victim.

Detectives collected that sock as evidence and now say it has Arteaga's DNA inside of it, and that was the lead off statement prosecutors told the jury as the trial got underway Wednesday morning.

"He forgot to take the sock," Deputy Prosecutor John Love said.

Tests later confirmed the gun was inside the sock as well as Arteaga's DNA.

Prosecutors say Arteaga shot and killed Schmidt because his long-time lover was rekindling her relationship with the father of her 12-year-old daughter.

"Kim Schmidt said Mr. Arteaga was her friend and he was her friend but not the way he wanted it to be. She was ready to move on. He was not," Love said.

Detectives said Schmidt was found inside her locked home New Year's Day 2012 and Arteaga admitted having been there the night of her death but that he left her very much alive around 3 a.m.

Schmidt's mom Toni went to her daughter's home to check on her welfare when Kim didn't pick up her daughter.

"I remember begging her not to be there and then opening the door and I could see her on the bed. I couldn't see her face or anything, it was covered," Toni Schmidt said, adding after being asked that her daughter's face was covered with a pillow.

Toni Schmidt had Arteaga on her cell phone when she realized Kim was dead. She said Arteaga reacted by saying he loved Kim more than anything else in the world and couldn't live without her. However there was no mention of love when Arteaga called 911 to report Kim's death.

Arteaga: Uh, uh, a report of a dead body.
Dispatcher: Where?
Arteaga: Uh … East 37 Regina. That is the residence of Kimberly Schmidt. Her mother was on the phone with me she had a bad feeling and she used a house key to get in and she found her on the bed.

The 911 call would stretch on for another five minutes before Arteaga showed any signs of emotion and only after Arteaga was asked to spell his last name.

The defense elected not to offer an opening statement but expected to blame Schmidt's murder on other people who had access to her home because there were no signs of forced entry the night she was killed.