New york — The cyberattack that took computer files hostage around the world appeared to slow on Monday as authorities worked to catch the extortionists behind it — a difficult task that involves searching for digital clues and following the money.

Thousands more infections were reported with the start of the workweek, largely in Asia, which had been closed for business when the “ransomware” locked up computers Friday at hospitals, factories, government agencies, banks and other businesses.

But the big second-wave outbreak that many feared they would see when users returned to their offices Monday morning and switched their computers back on failed to materialize.

Lynne Owens, director-general of Britain’s National Crime Agency, said there was no indication of a second surge in the cyberattack but warned, “That doesn’t mean there won’t be one.”

Security researchers in the meantime have been disassembling the malicious software, known as WannaCry, in hopes of uncovering clues to who released it. They are doing the same with the “phishing” emails that helped the ransomware embed itself in computers.