Witnesses become uncooperative on the stand all the time
I was in present in a homicide trial, which was for a friend of mine who was murdered, which wasn't funny, but the part that was:
An OG present for a gang shooting, that targeted his family home, gave statements to the gang detective. it's not snitching, he was just acknowledging that it was rival gangsters, it was recorded
A few years later, he testifies for the prosecution, and DENIES what is clearly him on the tape, in a typical OG way
"nah, nah, that ain't me, that don't even sound like me, see I had a medical condition around that time"
Dude had to be 50 years old, with a job, and everything, and made a fool of himself, but he stuck to his code lol I was on the verge of just breaking out in laughter, it was so comical. He was on tape saying his name. His address. His sons name. The date and time.
They didn't really even need him, they were just laying the foundation for a gang feud that led to multiple killings, my boys included.