From Examiner.com:

While backers of billionaire-funded Initiative 594 are planning one more rally this Saturday – using the Marysville-Pilchuck school shooting as something of a campaign prop – another county sheriff has joined 26 of his colleagues to oppose the measure, making the count more than two-thirds of the elected sheriffs against the measure.

From NRA:

A majority of Washington State’s 39 sheriffs have come out in opposition to anti-gun Washington State Ballot Initiative 594.  The sheriffs oppose I-594 because it will not make anyone safer, will strain scarce law enforcement resources, will criminalize the lawful behavior of millions of law-abiding gun owners in Washington and will be unenforceable.  Instead, I-594 would vastly expand the state’s handgun registry and force law-abiding gun owners to pay fees and get the government’s permission to sell or even loan a firearm to a friend or family member.

To date, 27 of the 39 sheriffs have publicly opposed I-594.