“The subject came forward,” said Ashley Savage, a police spokeswoman, and “was taken into custody without any incident.”

The police identified the man as Anthony Jones, 60. Mr. Jones, who is homeless, was being held without bail on a charge of unlawful entry, a misdemeanor.

Afterward, officers found Mr. Jones’s belongings — a backpack, clothes and bedding, according to NBC — in the attic. But Ms. Savage said the authorities did not know how long he had been living there, or any other details.

“When officers attempted to ask him questions, he did not comply or choose to respond,” she said.

On its face, the incident on Friday was a mildly eye-catching police blotter item. But it is also a street-level symptom of the vast national problem of homelessness. Indeed, Arlington announced a “10-year plan to end homelessness” — in 2008, nine years ago.