1.
If you ~ the truth about something, you gradually discover it.
They’ve pieced together his movements for the last few days before his death...
In the following days, Francis was able to ~ what had happened...
Frank was beginning to piece things together.
PHRASAL VERB: V P n (not pron), V P wh, V n P
2.
If you piece something together, you gradually make it by joining several things or parts together.
This process is akin to piecing together a jigsaw puzzle...
PHRASAL VERB: V P n (not pron)