(CNN) At a community event Tuesday night, Union City Police Chief Darryl McAllister talked with members of the Sikh community about how his department could work to prevent Union City from becoming the next California community rocked by an attack on a Sikh man .

A few hours later, he was shocked to learn that his own 18-year-old son was a suspect in one of the recent assaults.

"I am completely disgusted in sharing with you that, later yesterday evening, I received a call from the Manteca PD that the suspect in this horrific crime turns out to (be) my 18-year-old son," McAllister wrote in a note on the police department's Facebook page on Wednesday. He said his son has been estranged from the family for several months.

McAllister's son, Tyrone McAllister, has been charged with attacking Sahib Singh Natt on Monday morning.

Footage of the attack, released by the Manteca Police Department on Tuesday, shows the 71-year-old Natt being beaten by two people and spit on in broad daylight.

"Words can barely describe how embarrassed, dejected, and hurt my wife, daughters, and I feel right now," he continued. "Violence and hatred is not what we have taught our children; intolerance for others is not even in our vocabulary, let alone our values. Crime has never been an element of our household, our values, nor the character to which we hold ourselves."

Suspects kicked, spat on victim

Surveillance cameras from a nearby house captured the attack on Natt, which occurred around 6 a.m. on Monday morning.

In the footage, two people approach the 71-year-old and a confrontation ensues before they begin kicking Natt, causing him to fall to the ground.

He gets up, and seems to try to fight back, before he is kicked again, and falls back to the ground.

One of the suspects is seen in the surveillance video -- filmed from a nearby house -- continuing to kick Natt, before spitting on him and walking away.

The assault came just days after another Sikh man, Surjit Singh Malhi, 50, was attacked in Stanislaus County, outside of Manteca.

Union City is about 60 miles west of Manteca.

Son faces robbery, assault charges

The younger McAllister was arrested Wednesday morning. McAllister said he and his wife helped police locate his son.

According to Manteca police, Tryone McAllister faces charges of attempted robbery, elder abuse and assault with a deadly weapon.

Police have said they believe one of the suspects waved a gun in the air as they left the scene.

A 16-year-old boy was also arrested in the attack, Manteca police said.

Tyrone McAllister, 18, was arrested on Wedneday.

Manteca police spokesman Sgt. Stephen Schluer, in a statement issued Wednesday night, acknowledged the relationship between the chief and son, but said it "has nothing to do with the case."

Union City police echoed that sentiment in a statement, saying: "Chief McAllister's status as a law enforcement leader has no bearing or relation to the case whatsoever, but he is devastated by how much the nature of his son's actions are such a departure from everything he has stood for in his personal life and 37-year career of compassionate, engaging police work."

It was not immediately clear Friday morning whether Tyrone McAllister had an attorney.

Chief: 'My family is shaken'

McAllister said in his letter on Facebook that his son "began to lose his way a couple years ago," when he got involved with a "bad crowd." He has a history of "theft-related crimes," the chief said, and spent time in juvenile hall. McAllister said his son also spent several months in jail after being arrested as an adult.

Since getting out, his son "has been wayward," and has been away from home for months, McAllister wrote.

"My family is shaken to the core," he continued, adding that Tyrone's sisters -- one of whom is about to begin law school -- also don't understand the alleged actions of their brother.

"In the eyes of the public, no matter the irrelevance to the incident, the fact remains that the father of the perpetrator of this despicable crime is a police chief, period," he said. "One cannot expect the general public (our Sikh community in particular) to factor in any sentiment that would distinguish this from the integrity of my family name."

McAllister said he hopes the community, "in conjunction with my family," can overcome this obstacle and "be even stronger as a result."