But for many, these social networking sites are places where they try on disguises, mimicking tough or provocative identities often counter to their honor-roll reality.

For the police and school officials turning to these sites to monitor students and investigate crimes, navigating the space between pretending and endangering can be deadly.

Ryan Mills knows the cost of posting a photo that unsettled police.

Mills, 21, posed on Facebook with friends and high-powered guns. A deputy sheriff ended up shooting to death Mills' friend Peyton Strickland, an 18-year-old college student from Durham, during a botched raid in December in Wilmington. A grand jury decided last week that the deputy, who said he expected heavily armed resistance based on the Facebook picture, should not be indicted for fatally shooting an unarmed Strickland through the door.

University of North Carolina-Wilmington police and sheriff's deputies had gone to the Wilmington home of Strickland, a student at Cape Fear Community College, looking for a PlayStation 3 video game machine they suspected he and Mills stole.

Police feared that the guns pictured with Mills were in Strickland's house. Christopher Long, the deputy who shot Strickland, carried a .45-caliber submachine gun, a .45-caliber pistol, two extra pistol magazines, two extra sub gun magazines, a gas mask, a knife and a flash bang grenade, according to court records.

Long fired through the front door after mistaking the sound of a battering ram hitting the door for the blast of a gun.

"If I had even thought once that [the photo] could be misconstrued, or even worse, used against me or my friends by the people who are supposed to be protecting human life, I would have removed them," Mills said Friday, speaking publicly about the photo for the first time.

Two years ago, Mills tried out his new digital camera by snapping pictures of himself and his buddies posing with a friend's gun collection.

They spent the day target shooting, then goofed around at the licensed gun owner's house in Pittsboro, posing like tough guys with the unloaded rifles and handguns. In the photos, Mills is smirking; another friend is grinning.

Mills thought the photos were cool and posted a few to his Facebook profile. They joined a collage of pictures of college parties and beach trips.

An affidavit by Long filed as part of the grand jury proceedings last week shows just how much stock police put in Mills' Facebook photo.

Long said the mission that night was expected to be "extraordinarily dangerous." He described Mills' photo as "intimidating" and "hostile."

Long's team, he said in the affidavit, had been briefed that the "AR-15 firearms that we had seen in the photos and which were believed to be in the residence were capable of penetrating our body armor."

Mills said he can't believe officers made such a leap.

"Anyone looking closely at the facial expressions in the photo can tell it is just guys goofing on the guns," Mills said.

It is not clear why officers thought those guns would be in Strickland's house. Strickland is not in the photo. Mills did not live with Strickland. He lived in a townhouse three miles away; the address appeared in a campus directory.

Police found nothing but an unloaded hunting rifle and shotgun in Strickland's room at the other end of his house, said his father, Don Strickland of Durham. Peyton Strickland was a licensed hunter.

From friends to police

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