A tourist wearing an emoji costume allegedly broke into the enclosure housing internet sensation Punch the monkey.
The six-month-old baby macaque broke millions of hearts earlier this year after videos of him dragging around an orangutan plushie given to him as a substitute mother went viral online.
Video shows an individual dropping a stuffed toy on the ground inside the enclosure at Ichikawa City Zoo. A zookeeper then arrives and leads him away.
A second man reportedly filmed the bizarre encounter as it unfolded, with footage shared on social media.
The Ichikawa Police Department identified the suspects as American nationals Reid Jahnai Dayson, 24, and Neal Jabahri Duan, 27.
Both men now face charges of forcible obstruction of business, which they deny, a police official said. The Independent contacted the US embassy for comment.
