When Angus Crawford, a journalist at the British Broadcasting Corporation, started reporting on sexualized images of children on Facebook, he knew he had to proceed with caution. Mr. Crawford ... began investigating the presence of obscene images of children on Facebook last year, [and] found that pedophiles were using secret pages to share images of children. A subsequent police investigation led to one man being imprisoned. This year, [Mr. Crawford] followed up and found that there were still images on the website that appeared to break Facebook guidelines, which state that the social media company will remove any content that promotes sexual violence or exploitation. Mr. Crawford reported the images using Facebook's internal system, but the company took down only 18 of the 100 that he flagged. He then contacted the social network directly ... and was asked to provide examples of images that he had reported. When he provided examples ... the company reported Mr. Crawford and the BBC to the police. The company filed its report with the Child Exploitation and Online Protection Center. Facebook has said it is improving its system for reporting offensive content, but the incident has raised questions about exactly how it polices its site. Mr. Crawford ... noted an apparent contradiction between the view of Facebook's moderation system, which determined that the photos were not in breach of the social network's guidelines, and the company's decision to report the BBC to the police.