Marcel H
Marcel Hessehandout

German police on Thursday, (9 March) arrested a 19-year-old who is suspected to have killed his nine-year-old neighbour in the city of Herne. The search for Marcel Hesse began after the boy's body was found in the suspect's cellar.

Hesse then reported a fire at an apartment nearby, where police found a second body. The suspect has been described as a teen of a reserved nature and who was not previously known to authorities.

Officials said that the teenager posted a picture and video of the murdered child on the dark net boasting about the killing. Police also said that he posted pictures of himself next to the dead child.

The murder has shocked the city of Herne and locals have been gathering outside Hesse's apartment.

The discovery of the body on Monday triggered a manhunt with police using helicopters and sniffer dogs to search the area. Children in the city were told to play indoors in kindergartens because the police suspected the teenager could be armed.

According to a witness, Hesse had said on the messaging service WhatsApp that he wanted to kill himself but could not and so killed the child.

The family of the slain boy told local media that Hesse asked the boy for help with a ladder. The stepfather of the boy went in search of the boy and found his body in the cellar.

Investigators said that Hesse also mentioned online of an account of killing a woman, saying that she "put up more of a fight than the child".