From the article:

> On the ride back she filed a report online with Metro. Transit police called quickly. But the officer seemed to lose interest, she said, when she explained that the man hadn’t exposed himself. He had stuck his hand into his pants. It didn’t seem like a crime then, the officer said.

> A Metro spokesperson wouldn’t explain why police considered what the woman saw to be legal. As Express reported last year, Maryland is the only one of the areas Metro trains run through that requires genitals to be visible for something to be considered indecent exposure. D.C. and Virginia laws prohibiting public masturbation or simulated masturbation do not require visible genitals.