Luke said that the disciples of John the Baptist (οἱ μαθηταὶ αὐτοῦ) reported to John (Καὶ ἀπήγγειλαν Ἰωάνει) all these things (περὶ πάντων τούτων). Matthew, chapter 11:2, had something similar. John the Baptist heard about the works or deeds of Jesus the Christ, the anointed one, the Messiah, while he was in a prison. Clearly John still had a number of disciples, despite his imprisonment. Here Luke does not explicitly mention that John was in prison, just that a few of his disciples reported back to John the Baptist about Jesus and his activities. How do you learn about Jesus?
There was an Egyptian insurrection against the child king Ptolemy V (204-181 BCE), since he was only 5 years old when he took over as king. The various regents controlled his activities. Somehow, some of the Judeans of Palestine got involved with this, as they took sides on the battle between the kings of the north and the south, Egypt and Syria. However, they failed.