PLEASANT GROVE — Investigators had a hard time believing a Utah man didn't know his wife killed six of their babies and stored them in their garage, but they didn't have any evidence to pursue charges and eventually concluded he may have been so high on drugs he didn't realize what was happening, according to public records obtained by The Associated Press.

Under intense questioning from detectives after the April 2014 discovery in Pleasant Grove, Darren West repeatedly denied knowing of his wife's shocking actions, according to transcripts of police interviews obtained Monday.

West acknowledged that he knew of a couple of Megan Huntsman's pregnancies from 1996 to 2006, but said she told him she had miscarriages. West said he had no idea what his wife did with the fetuses or bodies.

That was, in part, caused by the fact that he spent most of the decade high nearly every day on cocaine, methamphetamines or marijuana before being sent to federal prison on meth charges, he said.

"I knew she was pregnant, but I was so messed up on freaking drugs I don't know what was going on," West said.

West did not immediately return a phone message but his attorney, Michael Esplin, said Monday that others around Huntsman who were sober also couldn't tell Huntsman was expecting a baby. Esplin said West was deeply confused and saddened by what Huntsman did, and had no involvement.

Huntsman pleaded guilty to six counts of murder and is serving up to life in prison. She said she was too addicted to meth to take care of the babies. A seventh baby's body was found, but investigators later determined it was stillborn.

She said during one birth, West was watching TV with his brother and sister-in-law when Huntsman told them she was going to take a bath and go to bed. Instead she gave birth, suffocating the baby.

Huntsman acknowledged wondering herself how her husband didn't realize she was pregnant so many times from 1996 to 2006. But she told police that she hid the pregnancies from everyone, including her three young daughters, including one born in between the newborns she killed.

During a long interview with Pleasant Grove police detective Dan Beckstrom, Huntsman reflected for a moment how her husband could have slept in the same bed with her every night and not known she was pregnant and why she didn't tell him.

"I think my mind was just so out of it you know," she said. "All I was focused on was the next fix."

With West's denials that Huntsman knew about the deaths, prosecutors didn't have a case against him, even though they openly wondered how West could not have known, deputy Utah County attorney Jared Perkins said this week.

"Obviously, the practical, reasonable thought would be how in the world could he not have known?" Perkins said. "That, I think, was the cause for the initial suspicion. … But in the end, there just turned out to be no evidence that would implicate him."

Police interrogated West on April 12, 2014, hours after West and one of his daughters discovered one of the bodies while cleaning out the garage shortly after he got out of prison, the transcript shows.

"I can tell that you know about more than, than what you're telling me," Beckstrom said to West.

"I promise. I swear to God I never knew about all these pregnancies," West said.

"What we want to do is we want to do what's right, and we want to have closure for these children," Beckstrom said. "We want to have closure for your kids that are alive, for these babies' grandparents. I mean these babies were in a garage for years."

"I never knew that, no, I never knew that," West said.