A woman who used to be close with accused Gilgo Beach serial killer's family says she was shocked to learn of Rex Heuermann's alleged crimes.

News 12 spoke with Lisa, who did not want to appear on camera. She says she knew Heuermann's wife, Asa Ellerup, very well.

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She says the family seemed like just a regular family. Their children had sleepovers and the families attended events together.

Lisa says she feels bad for Ellerup and does not believe she had any idea about her husband's alleged crimes.

MORE: ‘A devastating time’: Attorneys for Rex Heuermann’s wife say arrest has taken ‘emotional toll’ on family, request privacy

Meanwhile, those who live just doors away from the Heuermann home are more suspicious.

"I am just wondering how the wife had no idea about this," says Louise Colle. "You just can't do all of this and be able to keep everything a secret."

Colle also says the family was always inside, and she never saw anyone come out of the home.

Sources confirmed to News 12 that investigators believe one of more of the Gilgo Beach murders took place at Heuermann's Massapequa Park home on First Avenue.

Suffolk County District Attorney Ray Tierney says the murders took place while Heuermann's wife and children were out of town.

Ellerup's attorney released a statement, saying in part, "Ms. Ellerup does not want to comment further and has requested the public and press to please respect the family's privacy at this time."

Heuermann is accused of murdering three women and is the prime suspect in a fourth murder.

Detectives have searched his home, storage units and properties out of state.

WATCH: DOCUMENTARY AND BACKGROUND INFORMATION - Gilgo Beach: Unsolved

Heuermann's home continues to be searched.

Neighbors tell News 12 that the family has not been back to the house over the past week.