Friends of triple-homicide suspect Chris Watts say their decision to let him sleep over — in a bedroom across from their five year old daughter — in the days before his arrest for allegedly killing his wife and two daughters now haunts them “That’s something I’ll never forget, that we, we allowed this guy in our house,” Watts’ friend Nick Thayer said in an interview with Denver TV news station KUSA “I mean, had we had any inclination that we thought he was involved at all, no way would I have let him in my house with my wife and kid ” Watts was charged Monday with the murders last week of his 15-weeks-pregnant wife, Shanann, and the couple’s daughters, 4-year-old Bella and 3-year-old Celeste, during the time he was allegedly also engaged in an affair with a co-worker, according to an arrest affidavit obtained by PEOPLE Chris, 33, made his first appearance in court Tuesday but did not enter a plea He is charged with three counts of first-degree murder with deliberation, two counts of first-degree murder of a child under the age of 12 by someone who is in a “position of trust” over them, one first-degree count of unlawful termination of pregnancy, and three counts of tampering with a deceased body Chris was arrested Wednesday, two days after his wife and daughters were reported missing Aug 13 by another friend, and one day before their bodies were found Thursday on the property of an oil-and-gas company where Chris formerly worked Until the two Watts girls disappeared, they planned to spend last weekend at a sleepover with the Thayers’ 5-year-old daughter Emily, according to Nick’s wife, Amanda, the TV station reports “That would have been Emily’s first sleepover,” she said. Instead, after the girls vanished and Chris Watts made public appeals for his wife’s and daughters’ safe return, the Thayers invited Chris into their home to stay overnight, while also defending him on social media as speculation grew about his alleged involvement The Thayers said they placed him in a bedroom across the hall from their own daughter “She came in [the next] morning and was like, ‘I saw Mr. Chris,’ you know, ’cause I mean their doors are right by each other,” said Nick Thayer “It’s just a haunting memory at this point.” Neither Thayer said they knew of any troubles in the Watts’ relationship “Chris and I never talked about that kind of stuff anyway,” said Nick Thayer. Amanda Thayer said: “Shanann had jokingly mentioned it, but honesty she wasn’t worried But you know when your husband doesn’t answer your text messages, as a woman, your thought process just goes to the wrong things … It was never a serious concern of hers.” Following the arrest of Chris Watts, Nick Thayer said he reached out to Shanann’s family “I apologized,” he said. He told Shanann’s mother: “I’m so sorry, like, we didn’t know We thought we were doing the right thing” standing by Chris. He said a member of Shanann’s family responded to him over the phone, “We get it, we don’t hold it against you ” “That was a really big relief,” he said. “All I can do is say we’re sorry we defended him on social media … We really had no idea that he was capable of something like this.” The shocking turn of events left the Thayers wondering what they’d say to their 5-year-old about her friends “We have no idea,” said Nick Thayer, as he began to choke up. “I just looked at, while I was giving her a bath this morning and taking her to school, I just kept looking at her like, how do I tell you that your best friend’s gone?” According to the affidavit, Chris allegedly admitted to killing Shanann — but said he only did so after he “went into a rage” after, he claimed, he watched Shanann strangle one of their daughters Chris is due back in court Nov. 19.