Continuity mistake: The pad where the knife is stabbed protrudes under the writer's shirt.
Continuity mistake: When Jessica limps into Milton's car, she holds onto the door. A shot later, her hand is away, and it's Milton's hand instead holding onto the door.
Continuity mistake: When Jessica (a stunt double) is knocked down, her left arm is under her body with her bag in front. An instant cut later (now Angela Lansbury), her arm and bag are behind her back.
Continuity mistake: When Milton picks up Jessica at the airport, her bag is hanging over her right shoulder. A shot later, she is holding it with her left hand.
Funeral at Fifty-Mile - S1-E22
Continuity mistake: When Jessica walks from the house to the barn at the end, she is wearing knee high brown boots. By the time she reaches the barn they have been replaced with court shoes.
Chosen answer: This is the very reason my brother and I used to jokingly call the show, "Murder, She Caused." It's amazing she was ever on anyone's guest list for a party, given the likelihood someone would end up deceased. As to your question, most of the time, Jessica Fletcher would have had an air-tight alibi, as she was in a room full of people, or her whereabouts were accounted for when a murder occurred elsewhere. It also seems to me that there were episodes where she, purely with respect to opportunity, could have been a suspect. I believe she even acknowledged that as a logical possibility from time to time, even though she knew, of course, she was not the killer. However, the investigation would obviously rule out the possibility of her involvement, eventually.
Michael Albert