Thanks! I knew to stitch up is to sew with a needle and thread but I couldn't make any sense of police stitching the jury up this way. Thanks for your explanation. I guessed it must be a kind of an idiom but I wasn't able to find out what.
I'm not very sure about another attempt to gain a wrong conviction. I imagine the formulation "another try" indicates that the attempt wasn't successful but here it was – the singer is arrested.