FRANKFURT (Reuters) - German public prosecutors on Tuesday said they had brought charges against four people accused of operating an international underground child pornography website with 111,000 members.

In June, German police arrested a man suspected of operating the platform, known as “Elysium”, that was launched at the end of 2016 and only accessible via surreptitious communication protocols known as the “dark net”.

Frankfurt prosecutors said the suspects, aged between 40 and 62, would face up to 15 years in prison if found guilty on charges of serious sexual child abuse.

“The website had a platform with the title ‘Babies & Toddlers’ where members exchanged photos and video recordings of sexual abuse of children aged up to four years old,” the prosecutors said in a statement.

Of the four suspects, a 62-year-old man from the Bavarian town of Landsberg am Lech was charged with serious sexual abuse of two children aged four and six whose father, an Austrian citizen, had contacted him through the platform.

The father was prosecuted separately for child abuse.

The prosecutors said an investigation into the website’s users was still ongoing.