Milo Stanfield is a character from the Alternate Universe. His sister Madeline Stanfield was the one responsible for signing him up for a medical test treatment provided by the Ivon Medical Group that would increase the subject's intelligence so that they could function independently. He had a measured IQ of 56 but after the treatments, his intelligence increased dramatically.
At the end of the trial, the doctors were supposed to revert the subjects back to their former selves. As he didn't want that to happen he began to cause the accidents through the use of complicated mathematics, leading to the deaths of Cole Arnett, Jillian Foster and Jeffrey Mayer.
He is caught when he's unable to predict Olivia's behavior as he didn't know to factor in that she wouldn't follow protocol as the people of the alternate universe would. He is shot in the leg by Alternate Charlie.
In the end, the doctors were unable to reverse the effect of the drugs, as they had been in his system for too long, and he ended up being confined in an unknown medical facility where his thoughts are being interpreted by a computer.
It is unknown whether Stanfield's abilities were related to the Observer's ability to manipulate probabilities (calculative prediction).