Prosecutors said on Friday that the 27-year-old man from Traunstein was arrested on Thursday evening, after officials had released his photo to the public earlier that day.
The man is accused of sexually abusing the girl when she was eight to nine years old at least 26 times between 2014 and 2015. He took photos and videos of the abuse and shared them online to a child porn platform through the darknet.
The suspect had also posted photos of himself online.
"The fact that photos of the suspect were found on the darknet is unusual," said public prosecutor Georg Ungefuk.
Investigators had released the man's photo on Thursday, describing him as “dark blond” and likely with blue eyes. They said the release of the photo had brought in numerous tips and they were then able to identify and arrest him.
Investigators told DPA that they had a large amount of evidence and “substantial leads”. During a search of the suspect's apartment, police seized two computers, two smartphones, as well as USB-sticks and external hard drives.
So far there is no evidence of other victims.