Walker described the reasons he increased security in his book, “Unintimidated.” He wrote that Dave Erwin, who is now Capitol Police chief but previously was the head security agent for both Doyle and Walker, advised him to increase security because people were tracking his family’s whereabouts.

“Governor, I’ve been at this awhile, and when the hairs stand up on the back of my neck you have to be concerned,” Erwin told him, according to the book.

Walker also described some of the death threats that his family received.

One letter delivered to the Executive Residence addressed to Tonette Walker read: “Has Wisconsin ever had a governor assassinated? Scotts heading that way. Or maybe one of your sons getting killed would hurt more. I want him to feel the pain.”

Security agents have always provided round-the-clock security for the governor, regardless of event purpose, including for campaign-related travel, Webster said.

The Walker campaign has reimbursed the state $65,096 since January 2011 for use of state-owned vehicles to transport Walker and his wife, Webster said. Kleefisch’s campaign has reimbursed $28,970.