The writing is on the wall for the city’s lead ticket-fix investigator.

The NYPD has slapped Internal Affairs Bureau Detective Randy Katakofsky, whose Bronx ticket-fix probe led to charges against 16 cops, with a disciplinary action for bad penmanship, The Post has learned.

Katakofsky’s lawyer says the lowly charge smacks of payback.

“It looks retaliatory to me,” blasted lawyer Rae Koshetz.

Katakofsky is already facing NYPD departmental charges that he leaked inside information during the ticket-fixing probe to another cop, who was ultimately indicted in the scandal.

Now he’s been given a command discipline, in which the NYPD claims the cop made an illegible entry into a sign-in, sign-out log and also failed to make a memo book entry, according to his lawyer.

Katakofsky refused the command discipline and will now get a hearing.