Obviously his iphone didn't stand trial and say "He did it"
But...it basically did. Jeff West claimed that he was asleep the entire night and did not wake up whenever his wife was murder. He said he went to bed around 10:30 pm and did not wake up until 5:15 am. But his health app on his phone showed that he took 18 steps around 11 pm, right at the time of the murder.
There was also DNA on the murder weapon but the biggest blow was definitely the fact that his iPhone said "No you were wide awake"