Marvin LaFontaine, a friend of Nancy Lanza's, describes a young, shy Adam who did not like to be touched in the two-part PBS Frontline/Hartford Courant special 'Raising Adam Lanza.'

According to records, Peter Lanza paid Nancy yearly alimony totaling $240,000 in 2010; $265,000 in 2011; and $289,800 in 2012. Peter Lanza was solely responsible for the cost of college for Adam and brother Ryan. He also was responsible for buying Adam a car.

The Lanzas had joint custody of Adam, who was 17 in 2009, although he lived with his mother.

After the divorce, Peter Lanza continued to see his sons weekly, taking them skiing, hiking, rock climbing, to coin shows and on overnights at his Stamford apartment, the person who has recently been in touch with Peter Lanza said.

Peter Lanza often would help Adam with his math and science homework and described his son as "highly intelligent" and a "voracious reader," the person said.

But during the following year, 2010, Adam severed all contact with his father.

"Something happened with Adam," the person in touch with Lanza said. "Given the amount of time they were spending with each other, it was a sudden shift."

During this period, Adam also cut contacts with his brother, Ryan, who lived in Hoboken, N.J., and worked at a New York City financial firm.

Around this time, in 2010, Nancy Lanza was no longer in communication with her younger brother, James Champion, a military veteran and a ranking officer with Kingston police. Adam had looked up to his Uncle Jim, but Nancy began to discourage Adam from emulating his uncle, according to LaFontaine.

LaFontaine said he ran into Champion in Kingston in 2011 or early 2012 and asked him about his sister. By that time, after 10 years of regular contact, Nancy Lanza was no longer communicating regularly with LaFontaine.

"'I haven't heard from her in a while,'" LaFontaine said Champion told him. "And he looked down at the ground and he looked sad and he said, 'I don't know, she's not talking to me anymore.'"

LaFontaine said, "I thought, well, that's odd because she really loved her baby brother and so I wondered what had happened. I didn't ask him, I didn't think he wanted to talk about it, but there was something amiss."

Champion did not return phone and Internet messages for comment. When The Courant went to his Kingston home, a sign on the door asked members of the media to respect his privacy.

After the divorce, Nancy Lanza traveled more, leaving Adam alone for days at a time, something, she told friends, she was doing to encourage Adam to be more independent.

She went to fine restaurants in Connecticut and Boston and traveled to England, New Orleans and San Francisco on occasion, her friends said. In an email to LaFontaine after her divorce in the fall of 2009, she said she was in Boston "on a regular basis," and usually stayed at the Fairmont, the Four Seasons or the Ritz-Carlton.

When she went away, she would leave prepared meals in the refrigerator for Adam. She spent this past Thanksgiving in northern New England with family, one in a series of trips she took without her son.

"She was very comfortable leaving him alone for several days at a time," said Bergquist, who was friends in Newtown with Nancy Lanza.

Adam eventually earned his high school diploma, according to a person close to Peter Lanza. He also worked part time at a computer-repair shop in Newtown until it went out of business.

In the summer of 2008, when he was 16, Adam enrolled in classes at Western Connecticut State University. He did well, earning a 3.26 grade-point average. He received an A in a computer class, an A-minus in an American history class and a B in a macroeconomics class. He was given a C in philosophy, and he dropped out of a German language class.

His mother told friends that Adam embraced a more adult environment in college, but it didn't last. He was out in a year. In 2010, he enrolled in classes at Norwalk Community College but dropped out in the first semester.

After that, there was no more school for the 19-year-old. He sprouted to about 5 feet 10 and got his driver's license in 2010. He played the saxophone and a stringed instrument, and was studying Mandarin Chinese.