The people had declared that Nephi was a prophet (see verse 9 in this chapter). Their declaration saw him as a prophet declaring repentance, and so Nephi declares repentance, boldly, and specifically. He tells the people that “ye have rejected the truth, and rebelled against your holy God.” That surely called for repentance.
The prophetic declaration continues. He tells them that “even at this time ye are ripening … for everlasting destruction; yea, and except ye repent it will come unto you soon.” That is fully in keeping with the role of most Old Testament prophets.
However, Nephi also knows that many of the Nephites no longer believe him simply because he declares what they should have known. When they stop believing in God’s truth, they would also stop believing in Nephi. Therefore, Nephi is inspired to a more testable type of prophecy. He declares not only that the judge (presumably the Chief Judge) has been murdered, but he also declares that it was the judge’s brother who committed the murder. Finally, he lays the blame at the feet of the Gadiantons. That is what Gadiantons do. Mormon included the assassination of Cezoram at the beginning of the book of Helaman so we would understand that.
There is no chapter break at this point in the 1830 edition.