ANTIOCH, Calif. -- An Antioch couple was arraigned Friday afternoon for allegedly sexually abusing three family members between 1990 and 1998, but did not enter pleas.

Zion Dutro, 47, and Glenda Dutro, 45, were both referred to the public defender's office and issued three-year protective orders prohibiting any contact with the victims.

The charges against Zion Dutro include 21 counts of forcible rape, sodomy by threat, forcible lewd acts on a child under 14 and lewd acts on a child under 14 not by force, according to the complaint.

The charges against Glenda Dutro include four counts of forcible rape, forcible lewd acts on a child under 14, lewd acts on a child under 14, according to the complaint.

The defendants also each face an enhancement for sexually assaulting multiple victims and Zion Dutro faces an additional enhancement for having a prior sexual abuse conviction in 1995 against a child under 14, which required him to register as a sex offender.

Two of the three victims in the current case were under 14 years old when the abuse was happing, according to the complaint. The prior conviction was for sexual abuse of a fourth girl, according to Senior Deputy District Attorney Mark Peterson.

The couple was arrested at their home at 1915 Alpha Way on Wednesday, Antioch police said.

According to Antioch police Sgt. Diane Aguinaga, all of the victims were family members.

Police also said the abuse had been going on for the past 25 years and Senior Deputy District Attorney Mark Peterson said he would likely file additional charges against the suspects.

According to Peterson, although Glenda Dutro has only been charged in four counts, she was present in the house during much of the abuse and in some cases actively facilitated it. He described her as "an aider and abettor in the abuse."

"There were times when she would point to a certain individual and tell them it was their turn to 'cuddle' with her husband," Peterson said.

Zion Dutro also allegedly repeatedly threatened to hurt the victims and in several instances threatened to hurt the other victims if one victim didn't cooperate, according to the complaint.

Police said the three victims started coming forward to report the abuse when they heard the couple was planning to adopt children from Mexico, prompting an eight-month investigation.

If convicted of the current charges, Zion Dutro could potentially face a life sentence.

Zion Dutro is being held at the Martinez Detention Facility on $8.7 million bail and Glenda Dutro is being held at the West County Detention Facility on $2.4 million bail, according to a county jail official.

They are both scheduled to return for further arraignment Jan. 28 in Contra Costa County Superior Court in Pittsburg.