Updated

German police have launched a manhunt for a 19-year-old man who allegedly killed a 9-year-old boy in the western town of Herne and boasted about the murder on a video posted online.

The German news agency dpa reported Tuesday that the man bragged about the killing on the so-called darknet — an area of cyberspace invisible on the open internet often used for illegal activity.

Police have been searching for the man since the boy's body was found in the basement of a house in Herne on Monday night. Police in Herne couldn't immediately be reached for further details.

The authorities warned people in Herne and the surrounding region that the man, whose name wasn't released, knows martial arts and could be armed and dangerous.