I was doing some research and couldn’t find a source for this. This live wire was left in the attic and just capped off. My understanding is a live wire like this should be capped off and secured in a junction box. Can someone confirm or deny this? Also, if you have an educational resource for this with a link please post it.
Good find put it in Your report.
Live wire in attic needs an electrician to fix this immediately .
capped off and secured in a junction box
Yes!
Agree with Roy and Roy. 
Box, cover and wirenut or taping the ends off would be one fix, you could also just disconnect it.
And remove it…Correct?
Home Inspectors can not do either of these things .
You could, but removal is not required by the NEC.
Understood…
I agree, I was just providing another code compliant solution to the problem.