Two years ago, Matthew Weigman and his mother sat down with an FBI agent, and he was offered a second chance.
The 16-year-old had a reputation in hacker circles as one of the best around. His specialty was the phone system, and he was known for conning telecom employees into believing he was a colleague to gain access to unlisted numbers, the ability to shut off a rival's service or listen in on others' calls.
But the FBI agent who flew to his East Boston home offered him a deal. The blind teenager's name had surfaced in a nationwide investigation of a group of "SWATers" - people who manipulate the phone system to get police sent to fake hostage standoffs.
Dallas and Fort Worth were among the five dozen cities affected. In some cities, people were injured when police stormed their homes thinking a hostage situation existed.
Mr. Weigman was too young to be charged, so the agent made him an informant.
But, authorities say, he blew it.
The FBI says he tried to hack his way into the U.S. attorney's voice-mail system in Dallas. He told a witness who planned to testify against his "SWATer" friends that he would "injure and kill them and their family members, including in one case to kill a female witness' infant in front of her, if they were to cooperate with the FBI," according to an FBI affidavit.
Just after he turned 18 this year, authorities say, he persuaded an accomplice to drive him to the New Hampshire home of a Verizon fraud investigator, whom they allegedly threatened to harm if he continued working with the FBI on the Dallas SWATing investigation.
Mr. Weigman was arrested in June and charged, with at least one accomplice, with obstruction of justice. He is being held at the Mansfield Law Enforcement Center, and neither he nor his mother could be reached for comment. His attorney, Carlo D'Angelo of Mineola, declined to comment.
Mr. Weigman has pleaded not guilty in the case, which goes to trial Dec. 8.
The five SWATing defendants pleaded guilty in Dallas and this year were all sentenced from 2 to five years in prison. They came from all corners of the U.S., including Ohio, Houston, the Pacific Northwest and New York, but they met and plotted on little-known telephone chat lines.
Similar to Internet chatting, telephone chat lines enable people to dial in and talk in large and small groups. The lines are populated by a variety of people, including the geeky, socially awkward shut-ins who police say invented SWATing to get back at rivals.
"These individuals are reclusive," said Kevin Kolbye, assistant special agent in charge of the Dallas FBI, which has led the nationwide SWATing investigation. "They tend to have low self-esteem. They are not what they wish to be physically, so they use the anonymity of the phone to pretend they are someone else."
Most of the SWATers dabble in an offshoot of computer hacking focused on mastering telephone systems. "Phone phreakers," as they're known, are obsessed with pursuits that range from innocent to nasty, including monkeying with phone service, getting free features and spying on others' call records.
In a famous Dallas phone hacking case, a group known as the "Phonemasters" managed to forward the local FBI phone system to a phone sex line, resulting in thousands of dollars in charges.
For phreakers, SWATing is "an enormous power trip," said Matt Yarbrough, the former Dallas federal prosecutor who handled the Phonemasters case in 1999. "In a lot of ways, these people forget the human element in all this and the injury it can cause."
Being able to convince a telecom worker that you are a colleague takes an immense amount of study, Mr. Yarbrough said. "They Dumpster-dive and pull the telephone-system manuals and go online and absorb the training," he said. "They work harder than most of the people at the companies do."
To master social engineering takes a mix of technical know-how, the acting ability of an Oscar winner and the persuasion skills of a used-car salesman.
"Why pick a lock to a door if you can persuade someone on the other side to open it?" said Kevin Mitnick, 45, a former world-class phreaker who breached several companies' systems before the FBI caught him in 1995. He served five years in prison and is now a security consultant paid by companies to hack their systems, snooping for weaknesses.
He has studied Mr. Weigman's work.
"He was really good at persuading people to open that door," Mr. Mitnick said. "And since he's blind, his hearing is more acute and he's probably better able to read a person on the phone, and know whether someone is going to be cooperative."
According to the FBI, Mr. Weigman impersonated AT&T employees and managed to get several internal inquiries launched against other workers who were helping federal agents investigate him.
In late April, according to the FBI, Mr. Weigman zeroed in on the Verizon employee, repeatedly calling and harassing him at home.
When the investigator stopped answering the phone, according to court papers, Mr. Weigman tapped into the investigator's phone billing records in a ruse to get him to answer.
For instance, when the investigator made a call booking a flight, Mr. Weigman would capture that travel agency's phone number, mask his own Caller ID, call the investigator and make it appear the agency was calling. When the investigator picked up the phone, Mr. Weigman would continue his harangue, the FBI says.
On May 18, the investigator was working in his yard when a strange car pulled up to this house. Mr. Weigman, his brother and a 22-year-old friend who was driving got out, according to an affidavit.
Mr. Weigman introduced himself as "Matt." He told the investigator he knew he had been chasing him for two years.
The investigator said he couldn't talk to him, went inside and called 911. Mr. Weigman told arriving officers that the investigator had been harassing him and that he was there to talk to him about his "vendetta."
"If Matthew did what they said he did, it's a sad commentary on our society that these kids are choosing to do this and not applying to the National Security Agency and using their talents to find al-Qaeda," Mr. Yarbrough said.
What it is: SWATing is a trend among hackers who use technology to set up fake emergency calls for which police must react quickly by sending SWAT teams and other officers to the scene of a supposedly dangerous crime. The emergency calls appear to come from a phone at the scene, but when officers arrive, they find that no crime has been committed.
The danger: Heavily armed SWAT teams sometimes storm into homes, splintering doors or breaking windows. Innocent people, as well as the SWAT officers, can be hurt if homeowners react defensively without realizing the intruders are police.