The family of Kouri Richins, a Utah woman accused of fatally poisoning her husband before writing a children's book on processing grief, is speaking out publicly for the first time.

"We know Kouri's innocent, and all that's going to come out in court. And I think that's going to shock people," her brother, DJ, told ABC News in an interview airing Friday on "Good Morning America."

Kouri Richins, 33, faces a slew of charges, including aggravated murder, in connection with the death of her 39-year-old husband, Eric Richins, who was found dead at the foot of their bed on March 4, 2022, according to the probable cause statement in the charging document. The couple were married for nine years and had three young sons together, residing near Park City, east of Salt Lake City, according to his obituary.

"When I got the news that Eric had died, I broke down into tears," DJ told ABC News. "He was a good guy,"

"But it's my sister, I knew Eric, she didn't do this," he added.

Prosecutors allege that Kouri Richins poisoned her husband with a lethal dose of fentanyl in a Moscow Mule cocktail she made for him on the night of March 3, 2022. An autopsy determined that Eric Richins died from a fentanyl overdose, and that the level of fentanyl in his system was five times the lethal dosage. The medical examiner indicated the fentanyl was "illicit fentanyl," not medical grade, and that it was likely ingested orally, according to the charging document.

Kouri Richins' family, however, allege Eric Richins used drugs recreationally and possibly overdosed. Her defense attorney, Skye Lazaro, told ABC News there is no direct evidence that she ever purchased or administered fentanyl to her husband.

In April, while appearing on a "Good Things Utah" segment on Salt Lake City ABC affiliate KTVX to promote her new children's book, Kouri Richins said her husband died "unexpectedly." The dedication of her book, which was published in March, states it is to "my amazing husband and a wonderful father."

In recent days, prison guards searched Kouri Richins' cell and found a letter in which prosecutors allege she attempted to coach family and friends into giving false testimony on the stand. But her attorney said the letter was marked "attorney-client privelege" and should have never been opened in the first place.

Kouri Richins' brother accused jailhouse authorities of misadministering her medication "six times" to get her out of the cell so they could search it.

"One time is an accident. Two times is incompetence," DJ told ABC News. "Six times is -- looks like it's on purpose."

Both jailhouse authorities and prosecutors told ABC News that they could not comment on the letter and how it was obtained.

Several of Eric Richins' family members allegedly told investigators they "suspected his wife had something to do with his death," according to the affidavit for a search warrant.

"They advised he warned them that if anything happened to him she was to blame," the search warrant stated.

Prior to his death, Eric Richins removed his wife from his will and life insurance and was "looking into a divorce and wanted his kids taken care of," according to the search warrant.

The couple was also allegedly arguing over a nearly $2 million property she wanted to flip, according to the search warrant. "The day after Eric's death, his wife allegedly signed the closing papers on the home," the search warrant stated.

The search warrant also noted that in Jan.2022, Kouri Richins allegedly updated her husband's life insurance policy agreement with his business partner to make herself the sole beneficiary. The insurance company notified her husband and his business partner and they changed it back to being each other's beneficiary, according to the search warrant.

Kouri Richins' brother painted a very different picture, contending that the couple had a good relationship and describing his sister as a "great mom" who takes her sons to church every Sunday.

"At the time he died, I thought they were probably in the best place they've ever been," DJ told ABC News. "Kouri told the police that he didn't use drugs to protect his image."

Eric Richins' family disputes the claim that he used drugs.

"He was a person who took very good care of his health," a family spokesperson, Greg Skordas, told ABC News. "And so, to try to cast the light on him that we've seen recently is really troubling. It's really -- it's sad."

Eric Richins' sister, Katie Richins-Benson, has since sued Kouri Richins, accusing her of enacting a "horrific endgame" to steal money from Eric Richins, orchestrate his death and profit from it.

Kouri Richins is scheduled to return to court for a status conference on Nov. 3. A preliminary hearing date has not yet been set.