The grandmother of Richard Jefferson Saterfield, who is charged with the May 11, 2017, murders of Daniel Murti, 19, and Sergio Murti, 15 filed the lawsuit, along with Saterfield's mother and half-sister.
Saterfield's mother, Angelina Reynolds, 42, and his grandmother, Anita Garcia Lopez, 62 , along with Elizabeth Basquez-Procter, Saterfeld's 26-year-old half-sister were handcuffed, placed into two unmarked vans and threatened after they told detectives they didn't know any information about the whereabouts of Saterfield.
The three say they were then driven to a bowling alley parking lot where they were transferred to marked sheriff transport vehicles.
The women say they believe this was an effort to spread the word they were in custody in order to lure the Saterfield to surrender.
Their lawsuit claims they were held hostage at the Sacramento County Jail for days while police searched their homes and cellphones without warrants.
"It's pretty unusual," said Stewart Katz, the attorney who filed the lawsuit.
"They weren't arrested for a crime; they were arrested to be hostages. It's just painfully obvious; it was just a total abuse of authority."
Saterfield's grandmother was held in custody for three days before her husband posted her $100,000 bail on Mother's Day.
The other two women were held in custody for five days, even after Saterfield surrendered to law enforcement days before.
During their incarceration, Sacramento cops told the women they were suspected of being accessories to homicide.
However, upon their release, the Sacramento County Sheriff's Department presented them with certificates stating they had not actually been arrested.
Instead, according to the certificate, they'd only been "detained" and any records of their arrest would later be destroyed and deleted.
"The law requires that if someone is arrested and no criminal charges are filed they have to give you one of these certificates," Katz told the SacBee, pointing out the five days the two women served in jail was the maximum allowed before they must face charges or be released.
Saterfield's attorney was arranging for him to surrender to authorities on the morning of May 15, 2017 as the three women were being held in jail.
Instead, he phoned the department two days earlier, a Saturday, and informed them his client would surrender two days earlier than originally planned.
"The deputies' strategy of holding his female relatives hostage apparently had the desired impact of accelerating (Saterfield's) surrender as he turned himself in two days earlier than planned," the lawsuit says.
Starfield, who has a preliminary hearing in Sacramento Superior Court June 29, remains in jail without bail.
Hieu Van Hoang, 21, another suspect charged in the killings, also remains in custody.