2 Kings 15:14-16

Contemporary English Version

^14-16 Menahem son of Gadi came to Samaria from Tirzah and killed him. Menahem then became king. The town of Tiphsah would not surrender to him, so he destroyed it and all the surrounding towns as far as Tirzah. He killed everyone living in Tiphsah, and with his sword he even ripped open pregnant women.

Everything else Shallum did while he was king, including his plot against Zechariah, is written in The History of the Kings of Israel.