Alyssa Pladl has lost her firstborn daughter three times.

In an interview with DailyMailTV, she revealed why she originally gave up her baby girl, Katie, for adoption.

Katie Pladl would grow up to be a woman who married her birth father and gave birth to their child. She, along with her baby and her adoptive father, investigators said, were killed by the birth father in a murder-suicide, as Fox News previously reported.

Steven Pladl, 42, was found dead in early April in his vehicle in Dover, N.Y., several miles from the New Milford, Conn., murder scene where Katie Pladl and her adoptive father, 56-year-old Anthony Fusco, were discovered. Those two also were found dead in a vehicle that had one of its windows shot out, police said. The child’s body was found inside the couple’s home, hundreds of miles south in Knightdale, N.C., the same day.

In 1995, Steven Pladl was 20 when he met a 15-year-old girl named Alyssa on the Internet. She soon became pregnant and gave birth to a girl they named Denise.

“I knew from the very beginning that I had to get Katie away from him to give her a chance in life,” Alyssa told DailyMailTV, fighting tears. “Ultimately, Steve was just finishing off what he started 20 years earlier.”

Alyssa said her former husband would pinch their infant daughter Katie brutally until her body was left “black and blue.”

She also claimed he would stuff Katie in a cooler to drown out her crying until the baby was on the verge of suffocation.

Alyssa, then 17, said she knew the only way to ensure Katie’s safety was to put her up for adoption — the first time she lost her daughter.

Alyssa recounted that Steven Pladl remained throughout their life together “violent and angry, temperamental and unpredictable.”

She said Steven always had difficulty with a steady income, and was abusive.

“He threatened that if I was gone he would blow his brains out with a gun, figure out a way to record it and make sure the video got to me,” Alyssa told DailyMailTV.

As a child, Katie had been adopted by the Fusco family in Wingdale, N.Y., but after turning 18 she reached out to her birth parents through social media and expressed an interest in getting to know them.

Steven Pladl had two other children, ages 6 and 11, with Alyssa, when Katie moved in with the family.

Alyssa Pladl said she told Katie privately that Steven Pladl had abused her as a baby and that a major reason for the adoption was her own safety.

Katie, according to Alyssa, didn’t appear to be concerned.

Steven Pladl’s behavior changed after he met Katie, Alyssa Pladl said. He began wearing skinny jeans and form-fitting shirts. He shaved his beard and let his hair grow long. About six weeks after Katie moved in, Steven Pladl one night slept on the floor in her room.

It immediately concerned Alyssa. After he did it again the next night, she confronted him. He said it was none of her business and stormed out of the house with Katie.

Alyssa Pladl finally moved out in November 2016, and she shared custody of the two children with Steven Pladl.

The second time she lost her daughter: Steven told Alyssa last year that he had impregnated their daughter and planned to marry her after obtaining a divorce.

Alyssa initially learned Katie was pregnant by reading a journal of one of the younger children. Eventually Steven Pladl told his other children they were not to refer to Katie as their sister, but rather as their stepmother, court documents said.

Katie gave birth to Bennett on Sept. 1. She and Steven moved to a house on a cul-de-sac in Knightdale, NC.., just east of Raleigh, but wedded bliss did not last long. They were arrested on incest charges in January.

After the arrests, Katie moved back with Tony and Kelly Fusco.

On April 12, a Thursday, Katie and Tony Fusco left the Dover home for Waterbury. In a minivan nearby, Steven Pladl watched them leave, surveillance video shows.

Minutes later in nearby New Milford, witnesses reported someone opening fire. Katie and Tony Fusco, 56, were fatally shot. Steven Pladl was later found dead of a self-inflicted gunshot back in Dover.

Shortly after the New Milford shooting, as Fox News previously reported, Steven Pladl’s mother called 911 to report her son had told her he killed the baby, Katie and her adoptive father.

The Associated Press contributed to this report.