Victim's brother rips Colorado man accused of killing pregnant wife, two young daughters: 'May Satan have mercy on his soul'

A "heartless psychopath" is facing multiple murder charges three days after his pregnant wife and two young daughters were reported missing in Colorado.

Christopher Watts is being held at the Weld County Jail, the Frederick Police Department tweeted early Thursday. In addition to first-degree murder charges, he is facing three counts of tampering with evidence.

Investigators have not released any information on the whereabouts of 34-year-old Shanann Watts, 4-year-old Bella and 3-year-old Celeste.

A friend of Shanann's said she became concerned when the Frederick, Colo., resident did not show up for a doctor's appointment or answer her phone on Monday.

Photos of the family:

Before he was taken into custody, Christopher Watts told Denver 7 News, "I just want them back. If they're not safe right now ... that's what's tearing me apart."

Frankie Rzucek, Shanann's brother, wrote on Facebook that he just wants "30 seconds alone with that heartless psychopath."

"May Satan have mercy on his soul," he wrote. "The cops drug their feet. He was the only one with them and backed his truck into the garage. Doesn't take a genius to know who was suspect. My blood is boiling and the pain and anger and sadness I have in my heart. Nothing absolutely nothing would get in my way of taking away his life like he did mine and my ENTIRE FAMILY."

Shanann was 15 weeks pregnant.