WASHINGTON — Ever since law enforcement started seeing cases in the early 2000s, the crime known as sextortion has proliferated on the Internet, altering the lives of thousands and ensnaring victims from college campuses to military bases.

On Wednesday, the Brookings Institution will release two studies billed as the first in-depth reviews of sextortion — in which someone uses nude photographs of someone to demand ever more sexually explicit content or other goods — and its precarious place in a legal system that acknowledges its existence but has yet to write it into law.

“It’s about the security environment in a world in which anyone can attack anyone from anywhere,” said Benjamin Wittes, a senior fellow in governance studies at Brookings, an author of the studies. “When we’re thinking about that, we’re usually thinking about drone strikes or cyberattacks, which has all these same elements. We’re not usually thinking of sexual violence.”

Prosecutors say sextortion is increasingly common, with as many as 6,500 victims. It can involve hacking into victims’ computers to steal sexual images or even commandeer a webcam, then using the files to extort the targets.