[9] After Ashurbanipal's death, Sîn-šumu-līšir played a key role in securing the rise of his son Aššur-etil-ilāni to the throne, probably with the aid of his own private soldiers.

As the king's rab ša rēši, it is likely that Sîn-šumu-līšir played a role in suppressing the conspiracy, which appears to have been crushed relatively quickly.

[8] In addition to suppressing the revolt, there is also a preserved tablet which records a treaty imposed by Sîn-šumu-līšir on three private individuals, guaranteeing Aššur-etil-ilāni's sovereignty.

[8] It is possible that Sîn-šumu-līšir, as a prominent general closely tied to the king, was the de facto ruler of Assyria during Aššur-etil-ilāni's reign.

[2] Seeking to seize power for himself, Sîn-šumu-līšir quickly took some key cities in northern Babylonia, including Nippur and Babylon itself.

[16] In a later Babylonian epic, the killing of Sîn-šumu-līšir, in the story called the "almighty commander of the eunuchs", is attributed to Nabopolassar (the first king of the Neo-Babylonian Empire), rather than Sîn-šar-iškun.