A well-known Texas attorney who was found dead days after his daughter committed suicide died from an accidental cocaine overdose, officials said Thursday.

Brian Loncar, who was popular for a series of long-running television commercials billing him as “The Strong Arm,” was found dead in Dallas on Dec. 4, nine days after his 16-year-old daughter, Grace, took her own life and just two days after her funeral.

Loncar’s cause of death was the “toxic effect of cocaine,” a spokeswoman for the Dallas County medical examiner told The Post. Hypertension and cardiovascular disease were also listed as secondary factors, she said.

Loncar’s manner of death was “accidental,” the spokeswoman said.

The attorney’s relatives said they accept the findings that drugs caused his death, but said Loncar actually died from a “broken heart,” according to a statement to WFAA.com.

“The Dallas County Medical Examiner’s office released a finding that our beloved Brian Loncar’s death was caused by an accidental drug overdose,” the statement read. “While we accept this scientific finding, those of us who were closest to him already knew the cause of his death. Brian died of a broken heart.”

Loncar’s death directly followed his youngest daughter committing suicide after bouts of depression, relatives said.

“These are unimaginable losses for our family,” the statement continued. “Hopefully, these events will serve as heartbreaking reminders that we all need to reach out and care for our loved ones — every day.”

More than $50,000 has been donated to the Grace and Brian Loncar Foundation, which was created after the attorney’s death to “take the epidemic of teenage depression out of the darkness,” according to its website.

“Teenage depression is devastating families and communities across our country,” the site reads. “By giving teens a safe place to deal with their depression the foundation hopes to change that.”