The world Sam Nordquist inhabited through his phone screen was where he felt most at ease. It was where he found acceptance, established some of his deepest connections, met some of his closest friends.

The amount of time he spent socializing with apparent strangers online puzzled his friends and family, who knew him as an extrovert, a jokester, a charmer.

But it was not entirely surprising. He had dreams of fame, which he hoped to realize by uploading videos and livestreaming his everyday life, sometimes for hours at a time.

And for a young, Black transgender man living in the suburbs of Minneapolis with his mother and older brother, social media represented a landscape of endless possibility in his search for belonging, unbound by geography and often free of baggage or judgment.

Last September, he traveled to upstate New York to meet a woman he had begun talking to online over the summer. He considered her his girlfriend, even though they had yet to be in the same room. The trip was meant to last two weeks.

Five months later he was dead, his body discarded in the brush of a secluded farm roughly 15 miles from the roadside motel where she lived with her two young children. Mr. Nordquist was 24 years old.