MOUNTAIN LAKES N.J. (CBSNewYork) – Police in New Jersey are searching for a 15-year-old boy who went missing last week.

“He’s a good kid. I want to believe he’s on an adventure and there will be a day to say ‘don’t do that again,’ but we just want him back. We just want our arms around him now it’s time.”

Nicolai Kolding told CBS2’s Ali Bauman this as he tried to retrace his 15-year-old son’s steps.

He hugged Thomas goodnight Tuesday in their Mountain Lakes home. In the morning, his son was gone.

1105teen New Jersey Teens Disappearance A Mystery, Father Heartbroken

Missing teen Thomas Kolding (Credit: CBS2)

“Based on surveillance cameras we can see he boarded a train in Denville at 9:57. So we know he switched at Newark Broad Street and continued to Penn Station,” the father said.

“My mission is to try and figure out what cameras he might’ve been on, what security cameras so we can start to see his movement.”

The high school freshman left behind his cell phone, his laptop, and took about $1,000 from savings.

“He knew how to turn lawn mowing money, he invested it. He was a pretty savvy stock investor so he was a really bright kid.”

Thomas’ father says the boy’s disappearance is completely uncharacteristic.

“We talked to his best friends, looked them right in the eye, they’re just as shocked as we are. They can’t figure it out.”

Thomas did leave behind one clue.

“There’s a letter he wrote to a girl he’s very good friends with that basically said I need to go see the world and I’ll be back one day,” Kolding said.

New Jersey State Police posted his photo on Facebook and it’s been shared more than 20,000 times.

“We’ve literally been walking through the woods. I have the cuts on my hands and knees. We’ve been crawling through the drainage systems in Mountain Lakes,” the father explained.

“His 12-year-old brother… it’s tough on him. He hugs his empty bed every night.”

Thomas Kolding had one more message for his missing son.

“I love you so much. I love you. I miss you. I’m ready to listen and come on home it’s been a good adventure, but come on home.”

The father says his son always wanted to go to California, even though he doesn’t know anyone there. Detectives are talking to police on the west coast and keeping an eye on Thomas’ social media pages.