Unfortunately for the writer, Lutz's biggest critique seemed to be lack of proof and reasoning to back up her statement that she did not cheat on him.
"Long intro, short conclusion, strong hypothesis but nothing to back it up," Lutz wrote. "Details are important. If you want to be believed, back it up with proof ... Need to stop contradicting your own story and pick a side."
The grade was 61 points out of 100.
But he did offer her a chance to revise the letter for partial credit.
"While this gesture is appreciated, I would prefer details over statements," Lutz wrote. "Revision for half credit will be accepted. Good luck."
Photos of the letter were liked more than 300,000 times fewer than four days.
Other readers on Twitter were quick to point out more possible point deductions.
Brianna Chambers with the Cox Media Group National Content Desk contributed to this story.