PDF link to referenced grand jury report. Via

The analysis by the Grand Jury of the email cache of messages to and from staff in the District Attorney’s Office reveals that more than 25 staff members used County owned computers and the County owned and operated email system to solicit funds for a District Attorney candidate, sometimes in coordination with police officer unions in other cities and counties, to request attendance at campaign events, and to discuss campaign strategy during the 2018 campaign for District Attorney.

tl;dr basically O’Malley had staff campaigning on the taxpayers’ dime. Also apparently folks were specifically worried that they would lose their jobs if a progressive DA was elected:

The 2018 District Attorney election was the first, in recent memory, in which a sitting District Attorney was challenged. The Grand Jury learned that many staff of the Office of the District Attorney had very strong concerns about the outcome of the election.

The fear that the election of a new District Attorney, who had hinted at staff layoffs or terminations, was so overwhelming that staff failed to recognize their disregard of policies regarding campaign-related behavior as potentially illegal

Interesting since DA elections have become such a flashpoint in local politics in/around the Bay Area as center-right folks throw money at recalls etc.