PITTSBURGH » Klein Michael Thaxton hadn’t been much of a Facebook devotee. He posted no status updates in two years on the social network. On Friday, though, he surfaced with a jarring post: “i cant take it no more im done bro.”

The 22-year-old Army veteran was on the 16th floor of a downtown Pittsburgh office building at the time, armed with a hammer and kitchen knife, and holding a businessman hostage, police said.

He surrendered after more than five hours. Neither he nor the hostage, business owner Charles Breitsman, 58, was injured. But Thaxton’s real-time Facebook updates — coupled with online pleas by his friends to surrender — vividly illustrated the evolving challenges that confront police when social media plays an active role in a crime-in-progress.

In all, Thaxton sent seven messages, many of them despairing and written in disjointed style.

“this life im livin rite now i dnt want anymore,” said one post. “ive lost everything and I aint gettin it back.”

Thaxton’s friends responded by urging him to end the situation peacefully, including one who asked him to think of his mother.

“dude, you gotta purpose here in life, and this ain’t it yo, people do care man, they do,” another wrote.

Initially, police wanted the Facebook page kept open, hoping to gain useful information, but they later asked Facebook to take it down so that Thaxton could focus on communicating with authorities.

The Facebook exchanges had the potential to both help and harm those efforts, said Police Chief Nathan Harper. It was helpful that Thaxton could see “that people are concerned about his well-being,” the chief said, but “it is a distraction for negotiating.”

Hours into the standoff, Pittsburgh’s public safety director, Michael Huss, asked the media to refrain from reporting about the Facebook page, though many outlets had already done so.

Thaxton served as a private in the U.S. Army from December 2008 to June 2010. The Army said he trained at Fort Leonard Wood in Missouri before being assigned to Fort Riley in Kansas.

He also has a criminal record, including a guilty plea to robbery earlier this year in a special county court for military veterans with mental health or addiction problems.

The hostage-taking was the latest striking example of how Facebook and other social media can inject the public into crime dramas in ways that were inconceivable in the pre-Internet age.

In the old days, police would call the telephone company and ask that the hostage-taker’s phone number be changed immediately so no one else could call it, said Gary Noesner, a former chief of the FBI’s crisis negotiation unit.

In this case, countless people had the ability to communicate with Thaxton, sending him comments and potentially provoking him, “for better or for worse,” said Steve Jones, a professor who studies online culture at the University of Illinois at Chicago.

“We don’t really know what the perpetrators pay attention to,” Jones said. “Is he reading every post? How does he interpret those posts? What might set him off or what might get him to calm down?”

A former criminal profiling expert with the FBI, Mary Ellen O’Toole, said the decision by police to ultimately shut down Thaxton’s Facebook page made sense, just as there was reason to leave it up in the beginning.

“You really do have to be very careful. It may not take much to make that person even more erratic, more irrational,” she added, noting that negative posts “could really cause him to go terribly sideways.”

Harper said police counted 700 posts, most of them helpful to police in that they expressed concern for Thaxton or encouraged his surrender. But some were “ridiculous” and others “outright distasteful,” the chief said. If police determine any of the posts urged Thaxton to harm Breitsman or himself, those posters could eventually face charges, too.

Last year, a Utah man named Jason Valdez posted updates on his Facebook page during a 16-hour standoff with police. According to reports at the time, some of his friends and relatives urged him to “be careful” while at least one tipped him off to the location of a SWAT officer.

In another Utah case last year, a woman used Facebook to seek help after she and her 17-month-old son were held hostage at a residence for nearly five days. According to police, the woman hid in a closet with a laptop to post her plea for help, saying she and her son would be “dead by morning” if they were not rescued.

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Associated Press writers Kevin Begos in Pittsburgh and Michael Rubinkam contributed to this report. AP Technology writer Barbara Ortutay and AP news researcher Jennifer Farrar contributed from New York.