You have to take everything these people said with a grain of salt. All three were hard-core addicts. Even the police have stated numerous times there are holes in their version of events. Just because Lorna claims she wasn't on drugs that night doesn't mean she is telling the truth.
Regardless, she left her children alone all night in one of the city's worst neighborhoods. The oldest child that night was ten years old. Her history with drugs and alcohol have been well documented. I am not saying she was responsible for Tamra’s murder but her actions certainly didn't do much to prevent it from happening.
Cecelia Zhang was not at all abducted near by. She was abducted in Toronto, a major city. Regina's population was 179,200 in 2006 while Toronto's was 5,125,000. The cities are 2,686 KM apart.
There is a two hour window when Dean McArthur's whereabouts were unaccounted for. It was when Russell left to walk to the hospital to get stitches, after Dean assaulted him in the Keepness home. Dean claims it took him two hours to walk to his aunts house, which was only blocks away. He said that he walked there to go to sleep. This is during the time frame that Tamra presumably went missing. Why didn't Dean just pass out at the Keepness house? After all, he lived there.
Multiple publications who have interviewed police have said that Sheepskin stated it was Tamra asleep on the couch. I guess we'll never really know for sure. Time passes, people are influenced, memories start to grow a bit blurry. In any case, I feel confident that no bogeyman snuck in through a window and stole her. I mean, it's possible but definitely not probable.
I grew up in this city. I used to walk all around that area nightly. I met McArthur a year after Tamra went missing. I talked to him about that night personally. He didn't admit it to me but he said and did some very odd things.