Mao Sugiyama had got his penis and testicles surgically removed and frozen in March.
A month later the “asexual” illustrator defrosted his private part and cooked it up in public - serving the delicacy to customers at 160 pounds a time.
Police in Tokyo were not involved in the incident at the time, as it was not thought that any crime had been committed.
But now the mayor of Suginami ward, the district where the feeding took place, has asked officers to investigate following complaints from outraged locals.
It is believed that the charge relates to “the public display of obscene materials”, while safety inspectors are also looking into any violations of food hygiene rules.
“Many residents of Suginami and elsewhere have expressed a sense of discomfort and feeling of apprehension over this,” a major newspaper quoted Ryo Tanaka, the district mayor, as saying.
The 22-year-old had initially planned on eating his own penis but later opted to cook it for others.
On April 8, he had tweeted: “[Please retweet] I am offering my male genitals (full penis, testes, scrotum) as a meal for 100,000 yen...Will prepare and cook as the buyer requests, at his chosen location.”
The story went viral in his homeland - but only five brave diners came forward and actually tried the dish.
However, scores of curious locals attended the event, feeding instead on crocodile and beef.
Mao garnished slivers of the severed penis shaft, testicles and scrotal skin with parsley and mushrooms before serving it to the five willing customers at 160 pounds a time.
The Police have confirmed that they are investigating the allegations.