MANTECA (CBS SF/AP) — A suspect arrested Wednesday in the brutal assault of a 71-year-old Sikh man in Manteca is the estranged son of Union City Police Chief Darryl McAllister, who helped authorities apprehend him.

Manteca authorities said 18-year-old Tyrone Keith McAllister was one of two suspects arrested in the Monday assault of Sahib Singh Natt that occurred near Greystone Park and was captured on surveillance video.

Sahib Singh Natt (The Sikh Coalition)

A 16-year-old was also taken into custody.

The video shows one of the suspects kicking the victim to the ground. After the victim gets up to defend himself, the same suspect kicks him back down to the ground.

Police said they were treated the crime as an attempted robbery. They said Natt does not speak English and could not tell officers what the men said to him.

The Union City Police Chief said he was made aware of his son’s involvement in the brutal crime Tuesday evening. McAllister and his wife worked with the Manteca Police Department Wednesday morning, helping them track down and arrest their son at around 10 a.m.

In an open letter that Chief McAllister posted on the Union City Police Department’s Facebook page, he said he was “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 in my 37-year policing career.”

McAllister said that his estranged son “began to lose his way a couple years ago,” gradually moving from running away from home and “getting involved with a bad crowd” to more recent trouble for theft-related crimes as a juvenile and an adult that have led to time in juvenile hall and jail.

“Words can barely describe how embarrassed, dejected, and hurt my wife, daughters, and I feel right now,” McAllister said in the letter. “Violence and hatred is not what we have taught our children; intolerance for others is not even in our vocabulary, let alone our values.”

While McAllister said the word of his sons involvement in the crime left him feeling physically ill — “My stomach has been churning from the moment I learned this news,” he said in the letter – he also expressed gratitude for the kindness and support offered by the communities of Union City and Manteca in the wake of the news.

“You are the true spirit of character that makes this community so great,” the chief said.

It was the second assault of a Sikh man in a week. Last week, two men beat a Sikh man in Keyes and spray-painted a neo-Nazi symbol on his truck in what police are treating as a hate crime.

Surjit Malhi says he was putting up campaign signs for local Republicans when two men ambushed him.

Police do not believe the attacks are connected.

© Copyright 2018 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.