Opening arguments in Joe Arpaio lawsuit brought by Sen. Jeff Flake's son

Former Maricopa County Sheriff Joe Arpaio, pictured in 2013, received a pardon from President Trump last year. (AP/Ross D. Franklin)

Did former Arizona Sheriff Joe Arpaio doggedly pursue an animal cruelty case just to embarrass a U.S. senator who opposed his hardline views on immigration?

That’s the question now facing jurors in a malicious-prosecution lawsuit brought against Arpaio by Sen. Jeff Flake’s son Austin and his ex-wife.

Jurors heard opening arguments Tuesday, including the claim that the younger Flake suffered from depression as a result of the now-dismissed animal cruelty case.

The jury was told that Flake and his ex-wife Logan Brown still suffer emotional distress from the charges they faced when 21 dogs at a kennel operated by the younger Flake's in-laws died of heat exhaustion. The Flakes were watching the dogs while their in-laws were in Florida.

The couple's lawsuit alleges Arpaio pursued charges against them to do political damage to the Republican senator from Arizona and gain publicity for himself.

While jurors were told about Arpaio's efforts to publicize the case, the elder Flake was barely mentioned during Tuesday's opening statements.

Jeffrey Leonard, an attorney representing Arpaio and Maricopa County, said the charges against the couple were the result of a competent investigation.

Leonard also told jurors that the prosecutor who filed the charges was not pressured by Arpaio's office to prosecute the couple.

Arpaio lost his re-election bid last year after serving as sheriff of greater Phoenix for 24 years.

The case against the Flakes was dismissed at the request of prosecutors, and the owners of the kennel pleaded guilty to animal cruelty charges after an expert determined the facility's air conditioner failed because the operators didn't properly maintain it.

The federal judge presiding over the trial has determined previously that investigators didn't have probable cause to charge the couple.

The lawsuit alleges that Arpaio tried to link the senator to the dog deaths by conducting surveillance on the senator's home and examining phone records to see if the younger Flake called his father when the younger Flake was watching the dogs.

Lawyers for Austin Flake and his then-wife have said previously that the senator drew Arpaio's ire by disagreeing with the sheriff over immigration and criticizing the movement that questioned the authenticity of then-President Barack Obama's birth certificate.

Arpaio was known for carrying out dozens of large-scale immigration crackdowns and conducting a five-year investigation of Obama's birth record.

The allegations from the younger Flake came after Maricopa County paid $8.7 million to settle lawsuits from officials and judges who claimed Arpaio had launched criminal investigations against them on trumped-up allegations in disputes over budget cuts, a plan to build a new court complex and other issues.

The lawsuit by Austin Flake and his ex-wife doesn't specify how much money they are seeking. But they previously sought $4 million in a notice of claim, a precursor to a lawsuit.

Arpaio was convicted of criminal contempt in July for what U.S. District Judge Susan Bolton called his “flagrant disregard” of a 2011 court order to stop traffic patrols that targeted illegal immigrants.

President Donald Trump pardoned Arpaio in August, and in October, Bolton formally dismissed that criminal case against him.

Arpaio has criticized Bolton as biased and maintains that he did nothing wrong.

But as of last Friday, individuals who were detained from late December 2011 to late May 2013 in one of the illegal traffic stops can now begin seeking compensation from the local government.

Maricopa County will pay $500 for the first 60 minutes of each person's illegal detention, plus $35 for each additional 20-minute increment, out of a taxpayer-funded compensation system established as a result of the federal case against Arpaio.

The Associated Press contributed to this report.