Transit police in Boston are stymied by a string of robberies at stations along Bean Town’s subway system. They get their first break when a robbery victim refuses to give up his cell phone. The victim grabs one of the three youthful robbers and holds him down until police arrive.

The arrested kid, in an effort to save his own skin, gives up valuable information about his partners. He says they all share web pages on MySpace.com.

What the heck is MySpace.com? For those of you over 30, MySpace is the roaming ground of millions of teenagers. They pick a webpage name (free), get a secret password, and leave messages for friends.

Nearly every kid in America knows about MySpace. Hardly any 30-plus in America has ever heard of MySpace. Guided by this young robber, transport cops go to MySpace and find pictures and messages involving other gang members.

They read messages left on websites so gang bangers can keep in touch. They even find a picture of several gang members posing together — like one happy family.

Mug shots are taken to youth services with the belief that these kids are very likely repeat offenders. Bingo! Now the cops have IDs, and in some cases addresses. The noose is beginning to tighten.

Now detectives started lifting pictures of perps from video surveillance cameras at subway stations and matching them with pictures on gang members’ MySpace websites.

New technology is amazing. Boston continues to add surveillance cameras to stations along the Boston subway system. San Francisco long ago placed camera on light poles in high crime areas. In Columbia, S.C., video cameras are being installed on poles at strategic points around the city to spot crime as it happens.

Because of the human appetite to be seen on camera, cops will be able to compare criminals on police surveillance cameras with internet sites like MySpace to begin developing a "Who’s Who" in the underworld. Isn’t science great?

Our thanks to Bryan R. Ballou of the Boston Globe who first broke parts of this story.