New York (CNN) -- Justin DiPietro, the father of missing Maine toddler Ayla Reynolds, has taken a polygraph, the spokesman for the Maine State Police said.
"He was told the results," Stephen McCausland added.
McCausland would not say when the test was given, nor did he say whether Ayla's father passed, failed, or if the results were inconclusive. He also would not elaborate on what questions DiPietro was asked.
However, DiPietro told the Morning Sentinel newspaper in Waterville, Maine, that he took the test early on in the investigation.
"I know I went in there and smoked it," he said. "I told the truth, and that's it."
The newspaper reported Ayla's father would not reveal the results, and would say only, "They can tell me whatever they want. Again, I didn't physically see the results."
Polygraph results cannot be used as evidence in court.
It's been four weeks since Ayla disappeared.
Alya, now 21 months old, was reported missing by her father the morning of December 17. Police said DiPietro told them he put Ayla to bed at 8 p.m. the night before.
Police said Friday that three children -- not two, as they previously said -- were at home the night Ayla went missing.
Ayla's grandmother, Phoebe DiPietro, has told CNN that Ayla was in her bedroom she shared with her cousin, who is three months younger.
DiPietro now confirms to the Morning Sentinel that his sister Elisha -- the mother of Ayla's cousin -- was there along with DiPietro's girlfriend, Courtney Roberts, and her young son.
The family's one-story home is owned by DiPietro's mother. She told police she was not there that night. It appears DiPietro has a room in the basement.
DiPietro has not spoken publicly about what happened the night his daughter vanished other than to say, through his mother, that he put her to bed.
Investigators said they have told DiPietro family members they're free to discuss what transpired that night despite any previous possible misunderstanding. When Ayla first disappeared, police told them not to disclose details because of sensitivities of the case.
DiPietro told the newspaper he's deferring to police on that subject.
"I would rather let them be the ones to come out and talk about that night, if they feel it's necessary," DiPietro told the Morning Sentinel.
"I don't really feel that's up to us. If there are certain details they want to share, they should be the ones to come out and share those details," he told the paper.
A missing children's center in Houston, Laura's Recovery Center, said it has advised DiPietro to talk about Ayla as much as possible to keep the case in the public eye.