WATERBURY, Conn. — The biological mother of the Connecticut House of Horrors victim said it was “nauseating” coming face to face with his allegedly evil stepmom — as she revealed she has yet to be reunited with her son.

Tracy Vallerand was in court Friday — the second time this week — as Kimberly Sullivan pleaded not guilty to allegedly locking up and torturing her 32-year-old stepson for more than two decades.

“[Wednesday] was the first time I laid eyes on her and it was nauseating,” Vallerand told The Post of Sullivan’s first court date earlier this week in Waterbury. “They have the right to plead not guilty. But the evidence will prove that’s not the case.”

The stoic mother, who hasn’t seen her son since he was plucked out of school at 10 and vanished, vowed to attend every court hearing.

“I need to see justice done for my son. If he can’t be here, I will,” she said.

Vallerand said her son is being kept in an “undisclosed location” and that police told her he wouldn’t have access to anyone while the investigation into his decades-long alleged abuse continued.

She said she gave up the boy because of “personal issues,” believing she was giving him a better life with Sullivan and his dad.

Vallerand had no clue Sullivan would go on to allegedly lock the boy away in a small room inside their filthy Waterbury home for more than 20 years — leaving him so hungry and thirsty, he’d drink out of the toilet.

The victim, now 32, was just 68 pounds when he was rescued by firefighters Feb. 17 after setting a fire inside the home in a desperate bid to finally escape Sullivan’s clutches.

“I wanted my freedom,” he told authorities.

Vallerand, who lives in Meriden just 15 miles from Waterbury, said she and her family tried in vain to find the boy — with her ex-brother-in-law even hiring a private investigator.

“My daughter and myself were searching for him. The only thing you could find was a birth record. There was no death record so I had no reason to believe that,” Vallerand said.

Vallerand pointed her finger at Sullivan, saying: “The entire family was denied access to him” because of her.

“All parents are supposed to provide and nurture and help them become decent humans – not lock them in a room for life.”

Vallerand watched on Friday as Sullivan was allowed to remain free on bail, professing her innocence despite a judge calling the accusations “arguably the most troubling that I have seen in my time as a judge.” The biological mom bolted from the courtroom as proceedings wrapped up.

Later Friday, the allegedly wicked stepmother was spotted by The Post on an outside porch enjoying the sun — wearing a bucket hat and sunglasses and scrolling through her phone.

Prosecutors had tried to get her thrown in jail, saying that her victim, who has not been publicly identified, is living in constant “fear.”

Disturbing details of the real-life horror story were revealed earlier this month in court papers, which alleged the victim was kept in an 8-by-9 foot “back storage space” that was bolted shut from the outside. He told cops in a lengthy interview that he was given just two sandwiches a day to eat and had to relieve himself in water bottles and on top of newspapers.

The shocking horror story was revealed last month when he brazenly set the locked 8-by-9-foot room on fire, forcing Sullivan to call 911 and leading to his rescue.

By the time he was rescued, the victim hadn’t showered properly in two years or had a haircut in three, authorities said.

Prosecutors said when he was finally rescued, he was emaciated and “akin to a survivor of Auschwitz’s death camp.”

Sullivan, who posted $300,000 bail soon after her arrest, has repeatedly denied the sick allegations.

“I understand the whole world wants to convict Ms Sullivan and the whole world has,” her attorney, Ioannis Kaloidis, said in court on Friday as he argued against tightening her bail conditions. 

“But this is the only place, the only room, we have to protect her rights.”

“She is presumed innocent,” he continued, adding that “by adding conditions the court is sending the message that she has done something wrong.”