By Jessica De Nova/KTVL.com

SISKIYOU COUNTY, Calif. -- Siskiyou County Sheriff's Office expanded the crime scene perimeter in the homicide case of Michael Christopher MacCallum, 34, of Medford, finding additional evidence.

The Sheriff's Office arrived to the scene of the crime early Tuesday morning, not leaving until about 5:30 p.m., according to Siskiyou County Sheriff Jon Lopey. 

Sheriff Lopey says there were about a dozen investigators on scene, including Search and Rescue personnel.

He confirmed today that "a gun was involved in the crime and there were gunshots that were inflicted on the victim."

News10 spoke with Samantha Stacey, who claims she was engaged to MacCallum during the time he and his wife were separated. 

Stacey says, "Nothing is adding up [...] the different things that [she's] been hearing.  He went camping with his wife, friends, his sister-in-law [...] where are his kids and why would they go camping in the middle of a storm?"

Stacey adds she and MacCallum remained friends after MacCallum and his wife, Tricia, re-united. 

Tricia was aware her husband was seeing Stacey.  Tricia says both she and her husband were open to dating other people during their separation.

MacCallum's wife says she is "shocked" and "appalled" by the "insinuation" from investigators that she was involved in her husband's murder.  She says she and her late husband "were doing so well," and now she "will never know if they would have worked out."

When News10 asked Tricia MacCallum if she had any reason to or did murder her husband, she replied, "Seriously? [...] There's no reason for me to want him dead.  He was my husband.  I love him.  I need him.  He's our provider.  [...] I really don't know how to go on right now without him." 

Sheriff Lopey says there are still interviews to be conducted in Medford with MacCallum's family, friends and associates.  He says investigators are "identifying some investigative leads and are moving forward rather rapidly in the case."

MacCallum's father is now in Medford from California.

He and Tricia are making final arrangements for MacCallum. 

A memorial service in MacCallum's honor will be held on Saturday, Dec. 1, at 11 a.m. at Rogue Valley Fellowship, 2399 South Pacific Highway in Medford.

MacCallum's wife says anyone is welcome to the service.

MacCallum's family has started a fund to help them during these difficult times. Donations can be dropped off at or mailed to South Valley Bank and Trust on 600 Biddle Road in Medford. 

The bank will accept personal checks or money orders made out to the Michael Christopher MacCallum Fund.MacCallum crime scene reveals more