Arpaio's trip angered Mike Manning, a high-powered Phoenix attorney representing the veteran's family. He said it was inappropriate for the sheriff to leave town when he his agency is in such turmoil.
"This is a guy that needs to be attending to business in Phoenix rather than running around Iowa with a candidate who has no chance of winning," Manning told TPM.
Arpaio is campaigning for Perry in the final days before the Iowa caucuses. Several Republican presidential candidates courted the sheriff's endorsement this year. The Texas governor won out last month.
Arpaio's support for Perry comes at a strange time, though, with Arpaio's office facing new criticism. News spread recently that his office botched 400 sex crimes investigations. More recently, the Justice Department accused Arpaio of running an agency that routinely violates the constitutional rights of Latinos.
The Justice Department's accusations came Dec. 15, just hours before the veteran, Ernest "Marty" Atencio, was fatally injured in an altercation with officers in one of Arpaio's jails. He died Dec. 20 when his family gave doctors the order to take him off life support.
On Friday, Arpaio's office released hours of video, showing the altercation from 26 different angles. The video showed Atencio was standing with his arms folded when a Phoenix police officer grabbed him and tried to tackle him. As many as 12 officers from both the Phoenix Police Department and Maricopa County Sheriff's Office jumped into the fray. One of the sheriff's detention officers could be seen using a Taser on Atencio.
The officers then stripped Atencio, placed him face down in a cell and left him alone. The sheriff's office said last week that Atencio was still talking when they left him there, but the video shows he was nearly lifeless by that point. He stopped breathing soon after. The sheriff's staff didn't check on him again for 11 minutes.
Both the sheriff's office and the Phoenix Police Department are now investigating the death.
Because the sheriff's office released the video when it did, Manning said Atencio's family ended up watching the blow-by-blow of his final minutes just before Christmas.
"I don't think I've ever seen devastation like that before," Manning said of the family's reaction. "They are really inconsolable right now."
On Tuesday, Arpaio's chief political strategist said the sheriff went to Iowa this week because he made a commitment to Perry and he intended to fulfill it.
"The president of the United States is running around the country, going to Hawaii, playing golf," said strategist Chad Willems. "Everyone has a job to do. The sheriff is doing his."