He had used the image - reportedly taken from the French satirical magazine Charlie Hebdo - in a Year 9 religious studies lesson about freedom of expression.
He and two of his colleagues were reinstated to their positions in late May, after an independent inquiry found they had not meant to cause offence.
However, the unnamed teacher remains in hiding with his family, living in a secret location not known to even their close relatives.
A friend of his told The MailOnline: “On paper, he’s got his job back but returning to the school is not a possibility.
“An inquiry might have cleared him, but it doesn’t mean a thing because he doesn’t feel safe teaching there and genuinely fears that he could be killed.”
‘His two colleagues feel exactly the same. The matter needs to be resolved so that they can have a decent future,” they added.
Death threats were made against the individual after details of the lesson emerged, with angry protesters gathering outside the school in March.
This came five months after the French teacher Samuel Paty was beheaded in Paris for showing his students a satirical image of the prophet Muhammad.
When the investigation’s findings were released last month, the Batley Multi Academy Trust, which runs the west Yorkshire school, said it “deeply regrets the distress” caused by the row and vowed to make changes “immediately”.
It said that staff members did not need to use the cartoon “to deliver the learning outcomes on the subject of blasphemy”.
At the time, the National Education Union, which welcomed the decision to reinstate the teachers, said the Department for Education (DfE) should give clearer guidance to schools on how to teach difficult aspects of the RE curriculum.
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