Dallas Police Chief David Brown’s week from hell, in which a sniper murdered five of his officers at a demonstration, should have broken him.

It’s just the latest tragedy to strike Brown, 55, who has served the city’s police department for more than three decades.

In June 2010, Brown’s only son, 27-year-old David Jr., shot and killed two men — including a 37-year-old police officer — at an apartment complex in Lancaster, Texas, 17 miles south of Dallas.

He died in the Father’s Day shootout when officers returned fire.

Brown’s son suffered from bipolar disorder, and Dallas County medical examiners found traces of PCP in his system. His girlfriend had called police earlier in the day claiming he was suffering a “psychotic breakdown” and had struck her, according to reports.

The tragedy devastated Brown, who had been chief of the Dallas PD for a mere seven weeks.

“That hurts so deeply I cannot adequately express the sadness I feel inside my heart,” he told his department, according to a report.

While he was still deeply grieving the loss of his son, Brown called Keith Humphrey, head of the Lancaster Police Department, to set up a meeting with the families of the men his son killed, according to a Washington Post report.

“As I was walking out the door, I heard David say, ‘First of all, I’m sorry’ and ‘My son was not raised this way,’ ” Humphrey said, according to the report.

It wasn’t the first time Brown had grappled with the consequences of gun violence.

Brown’s younger brother Kelvin was shot to death by drug dealers in Phoenix in 1991. He has said little about the murder, only acknowledging to the Dallas Morning News, “The families of victims, I know what they go through.”

Prior to that, in August 1988, Brown responded to a police-involved shooting in Dallas that gravely wounded the officer — his former partner, Walter Williams.

Brown spent the night with Williams’ children after they learned their father had died at the hospital, according to a Morning News report.

When he became police chief in 2010, he told the Morning News he fully understood the effects on-the-job fatalities had on fellow cops.

“You lose a partner, you just never get over it,” Brown said.