“We can confirm an investigation against Christoph Metzelder on suspicion of sharing child pornography, including digital images,” a spokeswoman for the Hamburg prosecutor's office, Liddy Oechtering, told AFP.
The 2002 World Cup finalist is alleged to have used WhatsApp to send pornographic photos of children to a woman in Hamburg, Oechtering said.
The woman reported the images to the Hamburg police, who opened investigations alongside public prosecutors in August.
Oechtering confirmed reports that investigators had carried out raids in two locations on Tuesday, but declined to give further details.
According to a report in Spiegel magazine, the raids were on Metzelder's home and offices in Düsseldorf, and led to the seizure of a laptop and a mobile phone.
Oechtering said the footballer had not been detained, adding that “we are currently analyzing the materials seized.”
Metzelder played for major clubs such as Madrid and Borussia Dortmund in a career spanning 15 years.
He retired from football in 2014 and has since worked as a pundit for Sky Sports Germany and president of his local club TuS Haltern.
Since 2006, the 38-year-old has run a foundation in his own name to support socially disadvantaged children across Germany.
He has also recently appeared as a pundit on public broadcaster ARD, who said Wednesday that they had “suspended the co-operation until the accusations have been clarified”.
His is the second high-profile legal case involving a former Germany defender in two days.
On Tuesday, prosecutors in Munich confirmed that Bayern Munich defender Jerome Boateng was under investigation for a reported dangerous assault on his ex-partner.