Smartphone apps downloaded from Apple and Google can allow parents and other abusers to connect with pedophiles who pay to watch — and direct — criminal behavior.

After confirming the authenticity of the Bigo livestreamer with the authorities, The Times searched the Apple and Google app stores for other video chat apps. Reporters identified a sample of more than 80 apps that advertised children before stopping the search. They later contacted Homeland Security Investigations, the government’s main law enforcement group for international exploitation, for comment.

“The number one customer base paying for this abuse is in the United States,” the agent said. “It’s not like they are abused once a day. It’s 50 men getting 50 separate shows. They’ll wake up these kids in the middle of the night to be abused.”

Asked about The Times’s sample of offending apps, Mr. Sainz said a majority had been detected during the company’s standard review process, with an additional 20 taken down after an internal investigation in response to The Times’s findings.