Video (00:34) : Two Lakeville teenage sisters missing since April 2013 have been located at a horse farm in western Minnesota.

– Three police vehicles arrived at a west central Minnesota horse ranch Wednesday afternoon. Carrying a search warrant, police and U.S. marshals hoped to find evidence that would lead them to two Lakeville sisters who'd been missing since April 2013.

Instead, they found Samantha and Gianna Rucki inside a home on the ranch, "safe and in seemingly good health," Lakeville police said.

Less than four hours later, the girls left the White Horse Ranch in the back of a squad car, hunched forward and covered in a blanket. Lakeville police said Samantha, 17, and Gianna, 16, would be taken back to Dakota County, where the reunification process with their family can begin.

Their father, David Rucki, said Thursday that the girls are staying at a secure place where they are undergoing medical exams.

The sisters haven't been seen in public since shortly after they ran away from home in the midst of a bitter custody dispute in April 2013.

Wednesday's extraordinary discovery was the culmination of a renewed effort by authorities to find the girls, following a Star Tribune story in April that uncovered new information about the case. Lakeville police have accused the girls' mother, Sandra Grazzini-Rucki, of helping them get away from their father, but her arrest in Florida last month did not bring investigators any closer to knowing what happened to the girls. Grazzini-Rucki did not want her daughters to be found, her attorney said.

Gallery: Photo: Missing Lakeville girls found in western Minnesota Gallery: Photo: Missing Lakeville girls found in western Minnesota

Police suspected that an underground network of family court critics were hiding the sisters.

Lakeville police Lt. Jason Polinski said investigators were led to the White House Ranch after retrieving evidence from a search of a St. Cloud woman's home. The woman, Dede Evavold, is a supporter of the "Protective Parent" movement that argues the family courts are broken and frequently award custody to abusive parents. Evavold could not be reached for comment.

On its website, the White Horse Ranch describes itself as a nonprofit where abused children can heal by working with horses: "Broken children and hurting horses are able to bring each other to a place of healing through God's unconditional love." Situated among cornfields and prairie, the ranch is about 160 miles west of the Twin Cities.

Its founder and president is Gina Dahlen, who lives at the ranch with her husband, Doug, according to the website.

Doug Dahlen told the Star Tribune on Wednesday night that he was told by police he could not comment on the case. The White Horse Ranch website went offline mid-afternoon Wednesday.

In an interview earlier this year with the Valley Equestrian News website, Gina Dahlen said she grew up on a farm near Foley, Minn., and spent years as a pharmaceutical sales rep before feeling called to work with abused and neglected children through rescue horses.

Kari Hagstrom, the Equestrian News managing editor who lives in Elbow Lake, said she knows Gina Dahlen and has visited the ranch, but had no knowledge of the girls. Children don't live at the ranch; they just attend sessions with the animals, Hagstrom said. She described Gina and Doug Dahlen, who runs an engine repair business on the farm, as religious, and extremely kind and generous.

"They would be the last people I would suspect of having any nefarious doings," Hagstrom said. "I imagine they were trying to help someone out and not cause more harm."

The girls' father, David Rucki, said he got the call about 1:30 p.m. that his daughters were found, and since then had been working to find a place for them to stay until the family could come back together. He said he was relieved and happy that they were found, and now the process of reuniting with his daughters would begin.

Gianna and Samantha were 13 and 14 when they ran from their home on April 19, 2013, in the midst of the custody battle between their parents. They accused their father of abusing them. A psychologist concluded that Grazzini-Rucki had brainwashed the children.

In November 2013, a Dakota County judge granted David Rucki full custody of his children, saying there was no credible evidence of abuse. Rucki has denied ever abusing his children.

Lakeville police stepped up their investigation in April, after the Star Tribune reported the statements of a self-described witness to the girls' flight. Dale Nathan, a longtime critic of family courts and a suspended attorney, said that when Samantha and Gianna ran away, their mother picked them up in her car, and that he drove around with the three of them for two to three hours before he was dropped off.

Police obtained an arrest warrant last summer for Grazzini-Rucki. She's now at the Ramsey County workhouse, held on $1 million bail after her arrest Oct. 18. She's charged with three counts of felony deprivation of parental rights for her alleged involvement in the disappearance of her daughters. She was extradited from Florida and arrived in Minnesota earlier this month.

In an interview in April, Grazzini-Rucki denied having anything to do with her daughters' disappearance.

Michelle MacDonald, her attorney, repeated that assertion Wednesday. Evavold was the campaign manager for MacDonald's 2014 bid for Minnesota Supreme Court, but MacDonald said she had no knowledge of Evavold being involved in the Rucki sisters' disappearance.

"I am in disbelief," MacDonald said about Wednesday's events. "I hope [the girls] are reunited with their mother and brothers and sister, and even their father."

A police car was driven into a garage Wednesday near Herman, Minn., where it appeared that Gianna and Samantha Rucki were loaded into it. The girls had been missing since April 2013.

Staff writer Jennifer Bjorhus contributed to this report.