Photo/IllutrationThe apartment building in Neyagawa, Osaka Prefecture, where Mayumi Saito lives (Ryo Kato)

NEYAGAWA, Osaka Prefecture--A middle-aged woman was arrested here Nov. 21 after she confessed to dumping the bodies of four infants in plastic buckets, filling the containers with concrete and keeping them in a closet at her home for 20 years and more.

Mayumi Saito, 53, said she bore the children between 1992 and 1997, explaining that her former boyfriend was the father and that she did not have sufficient funds at the time to raise them.

She turned herself in to a police "koban" on the morning of Nov. 20.

Osaka prefectural police are having to tread especially carefully in this case as the cause of the infants' deaths remains unknown and the statute of limitations for abandoning a body is three years.

Even so, Saito was arrested on suspicion of transporting the body of one dead infant from a different location to the apartment she moved into in summer 2015.

Autopsy imaging has confirmed that four plastic buckets found in a closet of Saito's home in Neyagawa bear the remains of four infants.

The buckets were each housed in a cardboard box.

The police investigation will now focus on removing the cement-encased bodies and conducting a more detailed analysis to determine how they died.

"I gave birth to all of them at the place I used to live," Saito was quoted by investigators as saying. "I don't think (my boyfriend) was aware of what I did. I brought the buckets to my current residence with my other belongings when I moved."

She said she never reported the births to local authorities.

Her current residence is on the third floor of an apartment building. She told police she lives there with her teenaged son. Another son lives elsewhere.

Saito apparently moved the buckets from her old apartment sometime between mid-2015 and Nov. 20 of this year.

"I felt I would not be able to raise the children that I gave birth to, so I placed them in buckets and poured in cement," Saito said.

Police are eager to determine whether the infants were stillborn or died after they were born.

"There was no one I could talk to about my conscience and I thought about killing myself," Saito told police. "But I couldn't commit suicide and leave my son who I live with behind."

By Nov. 20, she felt she had to confess to police.