Robbie Lehman was convinced he made the right “life decision” when he left his Minneapolis home in February for Tanzania and the Peace Corps. The 23-year-old was fulfilling a dream to make a difference in the world.

But that dream ended abruptly Sunday when he was killed in a bus accident near the city of Mbeya.

In the few months that he worked as a community health volunteer in Tanzania, he was getting a better grasp of the language, the culture and the people, said his mother, Dr. Dawn Martin of Minneapolis. “Every time I talked to him, I heard a boy who was being transformed. He was more and more assured that he should be there. He loved it — the people he was meeting, his village. He was excited.”

Martin said her son and three other Peace Corps volunteers were returning to their separate villages on Sunday when the bus they were on tried to pass another vehicle. It hit another bus head-on, rolling four times before coming to rest in a creekbed, she said. Her son was thrown from the bus and died at the scene. The other volunteers were taken to a hospital to be treated for their injuries.

“It’s senseless and tragic,” Martin said. “It wasn’t supposed to happen.”

Lehman graduated from Edina High School in 2010 and St. Olaf College in 2014 with a degree in biology.

“There wasn’t a better match for the Peace Corps, in my eyes,” his mother said. “He had the spirit of compassion and he had the spirit of adventure. … He yearned for this.”

“Whenever there was an opportunity to join a mission trip, Robbie jumped right on it,” his mother said.

The tall, lanky young man with an effervescent smile and a strong sense of social justice was naturally drawn to people as much as they were drawn to him.

“I always thought of him like a golden retriever. Whenever he did anything, he did it with so much joy — the joy like a small puppy,” said Emily Karboski of Minneapolis, who got to know Lehman three years ago at St. Olaf. “You could throw him a Frisbee and he would be just so excited.”

He was an outgoing, easygoing, free spirit who loved the outdoors, she said. “He was the one who said, let’s go for a hike. And everyone would go. And then we would get to a freezing lake and he would say, ‘I’m going to jump in.’ ” He was a music buff who introduced new songs to his friends and was the first to break out “some crazy dance moves” at a party, Karboski said. But he also was a hard worker in school, she said.

He was funny, inquisitive and caring, said Tim Marburger, youth minister for the TRUST youth group in Minneapolis who was on mission trips with Lehman.

Working with homeless youth in Chicago, Marburger remembers the 6-foot-5 Lehman “looking like a maypole with all the little kids running around him,” he said.

“I read the last couple days that he wanted to be a citizen of the world,” Marburger said. “And his heart was big enough for that.”

“No, he wasn’t perfect,” his mother said with a laugh. “He wasn’t the most organized kid. He wasn’t a superstar academically.” Like many parents, they battled over grades or homework. “I wish I hadn’t battled so much over … ” her voice trailing off. “I think he wanted to spread his wings more, travel more when he was younger. But I was reticent and maybe I should have let him.”

But at 22 and 23 years old, her son was “hitting his stride,” Martin said. “You could see a kid who was going to thrive, grow and mature and figure out some wonderful things. … I’m going to miss him.”