Los Angeles Times reporter Alene Tchekmedyian had a big scoop: Internal documents showed that officials in the county sheriff’s department had tried to cover up an incident in which a deputy knelt on a jail inmate’s head.

But after her latest article about the blossoming scandal, Sheriff Alex Villanueva called a news conference to forcefully deny the allegations — and to take aim at Tchekmedyian. Standing in front of a placard with photos of the reporter, a political rival and the county’s inspector general, Villanueva announced the three were part of a criminal leak investigation.