The Pima County Attorney’s Office has declined to prosecute a Tucson police officer on charges of aggravated assault with a deadly weapon and disorderly conduct in recklessly handling a weapon.

However, Officer Michael Sauber Jr. was fired Aug. 8 after being placed on paid leave by the Police Department as it conducted criminal and administrative investigations into the incident, said Sgt. Pete Dugan, a police spokesman.

Dugan said Sauber was fired for “failure to meet and maintain standards.”

Sauber, a probationary employee who was hired in April 2016, was arrested after reportedly pointing a handgun at his father’s chest on July 28.

“There is insufficient evidence to prove beyond a reasonable doubt that a criminal offense was committed,” wrote Tom Weaver, chief criminal deputy for the Pima County Attorney’s Office, in an Aug. 22 letter to Tucson Police Chief Chris Magnus.

According to investigative reports, Sauber, who was off duty, was in the front yard of his parents’ house. After other family members labored to push a truck up the driveway in front of the house, Michael Sauber Sr. jokingly stated his son “always shows up after the work is done,” an uncle of the younger Sauber told police.

In response, according to the uncle, the younger Sauber “pulled a handgun from his waistband and pointed it at his father’s chest,” while the father was about 2 feet away, Weaver recounted in his letter. “Sauber Sr. then stated, ‘Do I need to shove that up your ass?’” The younger Sauber then laughed “as if it was a joke,” according to the letter.

Sauber Jr. denied pointing the gun at his father, but did admit he pulled it out and displayed it. Sauber’s father denied any exchange and told investigators that his son pulled his gun out because he was jostled about, and claimed his son did not point it at anyone, Weaver’s letter states.

Other family members interviewed gave differing accounts, and none corroborated that the gun was pointed by Sauber Jr. at his father.

“It’s not clear that the suspect intended to place his father or anyone else in reasonable apprehension of physical injury. Nor is there sufficient evidence to establish beyond a reasonable doubt reckless handling or display of a deadly weapon with intent to disrupt the peace of a neighborhood, family or person,” Weaver wrote in the letter.

Weaver wrote the decision not to issue charges “is based not on the arrest standard of probable cause, but rather on our issuing standard, which is whether there is a reasonable likelihood of conviction at trial.”

“Michael’s father vehemently denies the claim that a gun was ever pointed at him,” said Michael Sauber Jr.’s attorney, Michael Storie. “In addition, his uncle, who was right next to them at the time and has military experience in handling guns, also said that was a ridiculous claim.”

Contact reporter Carmen Duarte at cduarte@tucson.com or 573-4104. On Twitter: @cduartestar