Scottsdale PA officers spotted Ross Hurst spotted him easily, as he was wearing all black clothing in temperatures around 20 degrees.
But when patrolman Joseph Lane asked him why he had mud on his knee, his answer took them by surprise.
Hurst told them that he was acting out a fantasy of portraying a ninja, a Japanese martial arts expert employed for espionage and assassinations.
"I asked him why he was playing by himself, to which he replied that there are not a lot of people who want to play ninja," Lane stated in an affidavit.
"I advised him that it looked to me that he was doing something else. Hurst stated that he was not doing anything wrong and was going home."
Stunned by the story Trib Live reports Lane spoke with Hurst's sister-in-law, who said he has a 4-year-old son.
The 28-year-old , told them his mother was watching the child, but the boy's grandmother said Hurst never asked her to babysit.He has now been charged with endangering the welfare of children after he was found dressed in black and "playing ninja" on a street while his child was at home alone.