In a bit of revisionism, Jeremiah is suddenly in chains. An army captain notices this and sets him free. He gives him the choice to go back to Israel or come to Babylon with them. Jeremiah chooses Israel and is sent on his way with victuals and a reward (v. 5). He goes to live with the Babylonian-appointed governor in Mizpah.
The Jewish diaspora hears about the Mizpah colony and starts returning, including two by the names of Johnanan and Jonathan, who immediately start a rumour that the Ammonite king's representative, Ishmael, is really an assassin in disguise! The king dismisses them, because this isn't a bad movie-of-the-week, right?
Wrong. Ishmael and his men kill the governor and all his attendants in a scene worthy of inclusion on the 10 goriest of all time list. Nobody notices for 2 days. And then it gets even more like a bad horror film, as Ishmael and his men lure some innocent pilgrims back to the governor's mansion, only to kill them and throw their bodies into the toilet pit. 10 of the pilgrims manage to bribe him with food and escape.
Oddly, they do not warn the others, nor does Jeremiah, who has up until now been ever so eager to inform everybody about the consequences of god's wrath. So is this not divine punishment? Is it the work of a group of madmen? The commentaries are silent here. Jerry Falwell's only note on this chapter is about the construction of the cistern and even the slightly more serious scholars at biblos.com don't have much to say except that Ishmael hated worshippers of god. Clearly.
Anyway, Ishmael rounds up the rest of the people and takes them off to Ammon. Johanan, as crack a general as Jerry Falwell is a bible scholar, finally hears about the massacres and kidnapping and goes after Ishmael. Like many a bully, when confronted he turns tail without a fight. Johanan and the survivors take refuge in Egypt.
Jeremiah shows back up among Johanan's followers. They beg him to talk to god, like that has ever accomplished anything. God settles that whole problem of evil by saying If ye will still abide in this land, then will I build you, and not pull you down, and I will plant you, and not pluck you up: for I repent me of the evil that I have done unto you. (v. 10). As is typical whenever difficult questions about the bible arise, like whether god could be wrong and then admit ig, the commentators (or at least the evangelical ones) are pretty useless here. The best they can come up with is that god is now satisfied with the amount of punishment he has inflicted on his people and will now look for new sins.
Jeremiah has some more advice, namely to stay in Israel and accept the rule of the Babylonians. People who insist on going to Egypt will be punished with all those things god just apologised for.