The former Austin detective accused of killing his family had been charged with sexually assaulting his adopted daughter

• A former sheriff's detective accused of killing his family had been charged with sexual assault of a minor.
• He was accused of repeatedly sexually assaulting his adopted daughter, who the police say he killed.
• He was arrested Monday after a search. The details of this story may be disturbing for some readers.

The former sheriff's deputy who police allege killed his family in Austin, Texas, on Sunday was out on bond after he was accused of sexually assaulting his adopted daughter, court documents indicate.

The police say Stephen Nicholas Broderick, 41, killed three people: his estranged wife, Amanda Broderick, 35; his adopted teenage daughter, Alyssa Broderick; and her teenage boyfriend, Willie Simmons III. The Travis County District Attorney's Office has charged Broderick with capital murder in all three deaths, KXAN reported.

Alyssa had accused Broderick of sexually assaulting her in June, according to court records obtained by Insider. Alyssa, then 16 years old and identified in court documents by a pseudonym because she was a minor, had told her mother about an assault that occurred earlier that afternoon, the documents said.

Court documents said her mother took her to a local hospital for a sexual-assault forensic exam. At the hospital she told a nurse that Broderick had assaulted her, and the nurse who administered the exam noted injuries consistent with the teen's allegations, the documents said.

The teen also reported other instances of sexual assault by Broderick, saying that days earlier, on May 28, he raped her, according to the court records. Samples were collected at the time of the examination to determine whether Broderick's DNA was present, the documents said.

She told the police that Broderick had "continuously sexually assaulted" her since she about 10 years old, the documents said.

She said she had been hopeful the assaults would cease once she turned 16 but told investigators they had only worsened, according to the records. Each instance occurred at their home in the city of Elgin, outside Austin, the records said.

Broderick was also charged with multiple counts of assault by strangulation by "impeding the normal breathing or circulation of the blood of the said person by applying pressure" to the girl's throat or neck or by blocking her mouth and nose with his hand, the documents said.

A grand jury last summer indicted Broderick on nine counts of sexual assault of a child and three counts of family assault by strangulation.

Broderick worked as a sheriff's deputy in the Travis County Sheriff's Office from 2013 until his resignation last July, a spokesperson for the agency confirmed to Insider on Monday.

He was released from jail on a $100,000 bond last year, and a judge ordered Broderick to surrender all his guns.

Amanda Broderick had filed for divorce and a protective order against Broderick in July, around the time of the allegations. The protective order was granted in August, while the divorce was pending.

"Everybody's devastated," said Peter M. Lopez, the lawyer who represented Amanda in her divorce and helped her obtain the protective order.

"I think everybody was surprised. I can't tell you exactly what she thought, but I know that nothing like this ever came to our mind," he said.

Both parties agreed to the protective order in August, he said. It concerned only Amanda and her daughter, he added, because Amanda still wanted Broderick to have contact with their son.

"I don't think we ever thought this was possible," Lopez said. "I don't think she contemplated this, but I don't want to speak for her."

Lopez said he'd spoken to Amanda's mother and friends but didn't know of any public way to support the family.

Austin police said that at the time of the shooting, Broderick had been meeting his wife for a shared visit with their son, KXAN reported. The police said he rammed her vehicle and opened fire on the adults inside, killing them.

After a lengthy search, Broderick was arrested early Monday in the nearby town of Manor. The police said Broderick had a pistol in his waistband but did not resist when officers arrested him.