A Petaluma teenager missing since Monday was located, alone and unharmed, by authorities in New Jersey early Friday.

Justin Franz, 15, was found in the state capital of Trenton, at an Amtrak station near the border with Pennsylvania.

His parents, who on Wednesday announced his disappearance, had said they feared he was headed to New York City to connect with a Pennsylvania man he had met online.

The Casa Grande High School sophomore called home for the first time Thursday at about 7 p.m.

"I was just so elated, I was just jumping up and down and telling him that I love him and everyone misses him," said his mother Nanette Franz.

Speaking from Phoenix, Ariz., where he was waiting for a connecting flight to the East Coast, the teenager's father, Roland Franz, said his son did not meet with the man they suspect had tried to lure him across the country.

Using information Nanette Franz dug up on their son's computer, authorities located the man at his home in Pennsylvania, Roland Franz said. He did not know if authorities took any actions after contacting the man.

"That was our number one concern, that they got to him before they got to each other," said Franz, who earlier in the week said the man's communications with his son indicated he was a "predator."

The break came Thursday when Justin called home. Though he called from a payphone and quickly ran out of change, Petaluma detectives traced the call to Trenton and alerted New Jersey authorities, Roland Franz said.

At 4:57 a.m. Friday, New Jersey Transit police contacted Petaluma police to say they had found the teenager on a train and that he was safe.

The boy told his father Thursday night that he had headed to the East Coast to look at schools and never intended to meet anyone, Roland Franz said.

"He was testing himself, because he's so much kept at bay at home, and just proving he could execute a plan and prove he's not a child anymore. He's a young man," Franz said.

Justin acknowledged he had been communicating online with someone, but said he didn't know their age and the man had represented himself as lonely, his father said.

"Basically, Justin said that he had only returned the guy's messaging because he felt sorry for him," Franz said. "Justin swears up and down that he was not going to meet anyone."

In the family's well-kept, two-story house in north Petaluma, Nanette Franz was busy Friday fielding nonstop phone calls from well-wishing friends.

"Whew," she sighed at the home, which was decorated with Halloween ghouls, relieved that her oldest son would soon be home.

She was thankful for the media coverage and help from missing-children groups like the Polly Klaas Foundation. Getting the word out through the TV and print media may have helped lead to her son's safe recovery, she said.

Franz said she'd also been following the case of the 15-year-old Petaluma girl who was recovered in Central California this week with her 29-year-old godfather. Criminal charges were filed against the man, Hilario Matus-Carmona, Wednesday in Sonoma County Superior Court.

(Staff Writer Lori A. Carter contributed to this report.)