BRUSSELS (AP) — Prince Harry urged tech companies to be more transparent about issues involving children as he and his wife, the former Meghan Markle, made their first public appearance Tuesday since her father’s arrest on suspicion of possessing images of child abuse.

Harry spoke at the European Parliament in Brussels during the opening of a memorial to children who have died as the result of harm suffered on social media. The Lost Screen Memorial features replicas of oversized smartphones with the photo of a deceased child on each home screen.

Meghan, also known as the Duchess of Sussex, was originally scheduled to speak alongside Harry but withdrew because she was not “strong enough emotionally,” a person familiar with her reasoning said. She still accompanied her husband to the event.

The allegations against Thomas Markle Sr. surfaced last month. He was ordered to jail Tuesday because he removed an electronic monitoring device from his ankle, just days after he was charged with possession of child sexual abuse material.