(NBC News) — Friday on a special “Dateline NBC,” Lester Holt reports on Anton Black, a 19-year-old who died while being taken into police custody.

The year-long “Dateline” investigation reveals new details and looks at warning signs the town received about the office at the center of the case.

Here’s a preview of Holt’s report:

You’ve probably never heard of Anton Black and neither had we. We found out about him while reporting on a case you have heard of — the murder of George Floyd under the knee of officer Derek Chauvin.

This story is about the kind of incident that occurs all too often. But, unlike George Floyd, seldom makes national news.

ANTONE BLACK: Yeah, this is my baby boy, Anton.

Anton was a standout athlete, voted his high school’s homecoming king — twice.

ANTONE BLACK: He was a star, wide receiver on the football team. And mid-Atlantic champion in the 100, 200 in the high jump. He was a very exciting young man to see, I used to love to see him run, oh, and jump.

After graduating, Anton enrolled in college. But in that summer of 2018, Anton’s behavior changed.

ANTONE BLACK: To me all of a sudden he — he got moody. He was crying. He was upset all the time.

LESTER HOLT: He went to a hospital?

JENNELL BLACK: Yes.

Anton was diagnosed with bipolar disorder, a condition that often develops in the teenage years. He spent a week in the hospital. Ten days after he was discharged, Anton was dead

Watch “Dateline: What Happened to Anton Black” Friday at 10 p.m. on NBC4.

About ‘Dateline’

“Dateline NBC” is the longest-running series in NBC primetime history and is in its 30th season. Dateline is anchored by Lester Holt and features correspondents Andrea Canning, Josh Mankiewicz, Natalie Morales, Keith Morrison and Dennis Murphy.

Dateline is the #1 Friday newsmagazine and reaches more than 17 million people every week through its broadcast, and millions more through its social media platforms and podcasts.

The stories range from compelling mysteries to powerful documentaries and in-depth investigations. When major news breaks, they go to the scene, putting the pieces together to bring the viewer the full picture. And in every story they tell, they help the real people who lived the events share their journeys with the viewer.