Earlier this year, Kik Messenger user "heyyyydude1" was selling a stash of videos he'd amassed of child sexual abuse. One customer, who said he was a 35-year-old father of two, offered to buy 200 videos for $45. "How do I pay?" he asked. "Cash App," heyyyydude1 responded, sending over his payment details and a code for a Cash App referral fee. With each transaction, and many more disturbing videos sent, the seller was unknowingly providing a pile of evidence to an undercover agent with the Immigration and Customs Enforcement's child exploitation unit. Current and former police, as well as nonprofits working directly with cops to fight child exploitation, say that such crimes are often happening via Cash App, which brings in billions in gross profit every year for Block, Inc., the Jack Dorsey-run payments giant formerly known as Square. They say that whether it's to pay for sex with a minor, to send children funds in return for nude images or to traffic a young adult victim, Cash App is often the payment tool of choice. Though it recently launched a Cash App for Teens feature, the company is conspicuously absent from collaborative efforts to fight abuse, failing to provide any tips to the National Center for Missing and Exploited Children (NCMEC), America's national clearing house for sexual abuse material found on tech platforms. Hundreds of pages of court filings describe cases where law enforcement said Cash App was used to either pay for sexualized images or sex with minors and adults.