Tumblr staff helped nab an alleged pedophile after he used his blog to brag about sexually abusing a young girl and to post graphic images of child abuse.

Houston police arrested Richard Benjamin, 37, on Jan. 7, charging him with three counts of possession of child pornography and child sexual abuse and two counts of aggravated sexual assault of a child. Benjamin apparently confessed shortly after the arrest, admitting that his social media brags were no fantasy, and that he’d abused the girl in question.

He “claimed to be grooming her for more sexual abuse,” the Houston Chronicle reports.

Authorities found sexual images of the girl in his home and, perhaps more disturbingly, more child porn on his cellphone.

According to the Chronicle, Tumblr staff alerted the national National Center for Missing and Exploited Children when they saw unusual behavior on his account. They tied that account to Benjamin’s private email, which led police to his real identity.

He’s being held in Harris County jail for $200,000.

Tumblr did not respond to a request for comment.

Photo by Casey Serin/Flickr