My initial assessment is that the defendant, Mary Barnett, is guilty.
I think that Mary Barnett should not leave her six-month-old daughter, Alison, unattended in the apartment because she would like to visit her fiancé in San Francisco. I do not understand how mother can leave her child unattended and how she can do it for the sake of man. I think that Mary should find someone who could take care after baby for a while. She could ask her parents, friends or neighbors to help if she did not want to take the baby with her. Therefore, my questions are why she did not take her baby with her to trip and why she probably wanted to kill her child. I think, she probably did not want her fiancé to know about Alison. Secondly, she did not tell him that she had any children. Third, the fiancé refused Mary because of the daughter; he did not want any children at all. Probably Mary gave birth to Alison for holding her fiancé. She was really in love with him and when he left she was depressed and did not pay any attention to the conditions of child' well-being. She thought only about her fiancé. .
If we can confirm any of these suppositions, we will arrive to the conclusion that Mary Barnett wanted to kill her baby and did it purposely. Therefore, she is definitely guilty.
Was she aware that she can kill her child by leaving him unattended for the week. I think she understood what she had committed the crime because she lied and told to police that she had left her baby with a baby sitter. Probably she did not plan it as well as professional murders do, but she understood that her baby could die without water and food after few days. Even later, she stated that she knew that she had left her baby behind, that she did not intend to come back and that Alison would die in a day or two. .
I do not know for a while what kind of person Mary was, what kind of problems she faced, and what exactly could push her on perpetrating this crime.