Former Maricopa County Sheriff Joe Arpaio was unable to cite any evidence while on the witness stand Wednesday in a malicious prosecution suit filed by the son of Sen. Jeff Flake.

Last month, Flake’s son Austin filed his suit against Arpaio, saying the sheriff pursued charges against him and his then-wife in 2014 for the deaths of 21 dogs at a kennel his in-laws managed.

The case was later dismissed.

Arpaio told jurors Wednesday that he had enough evidence to prove the dogs died of heat exhaustion, but couldn’t explain his confidence in that, The Associated Press reported.

“Once again, I don’t have the nuts and bolts,” Arpaio said. “The detectives handled it.”

Austin Flake’s suit claims that Arpaio’s case was meant to do political damage to the Arizona Republican senator and burnish his own image.

Prosecutors requested the case against the Flakes be dismissed and the owners of the kennel eventually pleaded guilty, saying the air conditioner failed because operators didn’t properly maintain it.

Austin Flake claims the distress led to the demise of his marriage to Logan Brown. 

Arpaio was unable to explain why he told reporters the deaths were suspicious after Arpaio’s spokesman called it a tragic accident the day before.

“What turned it from tragic accident to highly suspicious in 24 hours?” asked Stephen Montoya, who represented Flake and Brown.

“I don’t know,” Arpaio responded. “Maybe someone had an opinion.”

Arpaio was also asked by Montoya whether he knew making a criminal case against the son of a senator would give him national attention.

“I don’t know,” he said, adding that he doesn’t consider a person’s last name when pursuing a case.

Flake and Brown’s lawyers said that Arpaio had a vendetta against the senator for disagreeing with Arpaio’s hardline stance on immigration and questioning President Barack Obama’s birth certificate.

Jeff Flake, on the other hand, criticized the “birther” movement and supported comprehensive immigration reform.