motive

Investigators have been trying to establish a motive for the killing.

Officials were expected to release charging documents against Robinson on Tuesday that could contain more information about a motive.

A motive has yet to be determined.

Although investigators have not determined a motive for the assassination, right‑wing media, pundits and some Republican politicians were swift to blame leftist rhetoric broadly.

"We're interviewing all kinds of people - everyone that knows him - and trying to learn more about what the motive actually was," Cox said.