The FBI is searching for a York Township woman who agents say kidnapped her infant daughter in March and fled to New Zealand, federal court records show.

Bianca Ellen Ormsby, 21, of Beaver Crossing Lane, is charged with international parental kidnapping, according to a criminal complaint filed Tuesday in federal court in Detroit.

Ormsby, who was born in New Zealand and has citizenship there, also was charged last month with kidnapping-custodial interference after an investigaton by the Washtenaw County Sheriff’s Department, county court records show.

Ormsby fled the country March 16 with her daughter, Sydney Thomas, according to an affidavit supporting the complaint by FBI Special Agent James Brennan. The two traveled on a Qantas Airways flight to Auckland, New Zealand, that departed Los Angeles International Airport, the affidavit says.

At the time, Ormsby and Sydney’s father, 21-year-old Adam Thomas, had temporary joint legal custody of Sydney, who was 10 months old, records show.

Under the arrangement, Thomas had Sydney for three days, while Ormsby would take her for the next four, the affidavit says. Then, Thomas would spend four days with Sydney and Ormsby the next three.

On March 9, agents say, Ormsby picked Sydney up from Thomas’ home in Farmington Hills, where he lives with his parents, the affidavit says. There was nothing unusual about the visit, Thomas said. But he hasn't seen Sydney or Ormsby since. Three days later, Thomas went to Ormsby's home in York Township, where she was living with her parents. He was scheduled to pick up Sydney at 7 p.m. under the court-ordered arrangement.

"The house was completely dark," he said.

Thomas attempted to contact Ormsby by phone and e-mail and got sheriff's deputies involved. He said he received an e-mail from Ormsby on April 11, indicating she was in New Zealand and thought being there was best for Sydney. Thomas is eager for Sydney's safe return. Sydney had just learned to crawl the last time he saw her.

“She’s a really good kid,” Thomas said. “She doesn’t cry really at all. It’s all smiles. She’s a real easy baby. She’s beautiful.”

FBI Special Agent Sandra Berchtold, a bureau spokeswoman in Detroit, said on Thursday she did not have additional details on the investigation.

If Ormsby is convicted of the federal charge, she faces up to three years in prison.

Lawyer Kirsten McNelly, who represented Ormsby in the past during the custody battle for Sydney, could not be reached for comment Thursday. Ormsby's father, Dr. Adrian Ormsby, did not return a phone call seeking comment Thursday.

Bianca Ormsby and Thomas had been dating for a couple of weeks when Ormsby, a former University of Michigan student, became pregnant with Sydney. The couple lived in an apartment in Ann Arbor until the end of 2008, then moved in with Thomas' parents. Sydney was born May 9, 2009, at St. Joseph Mercy Hospital in Superior Township, records show.

The couple planned to raise Sydney together and moved into an apartment on East Washington Street in Ann Arbor on July 1, 2009. Thomas was working full-time as a vacuum salesman.

"I was trying to do what was best for Sydney," he said. "I was trying to do that from day one. I worked and paid for everything."

But by mid-July 2009, the couple had separated. Ormsby alleged Thomas was verbally and physically abusive. She obtained a personal protection order against him on July 24, 2009, but it was terminated at her request two months later. During the custody battle, Thomas expressed concerns about Ormsby's mental state, noting that she was hospitalized July 17, 2009, after taking an excessive amount of pain medication, court records show. He also expressed concerns to the court as early as July 2009 that Ormsby might flee to New Zealand with Sydney.

"If there was ever an argument she would make the threat," he said.

According to the affidavit, Ormsby and Sydney traveled with New Zealand passports. Thomas was not aware a passport had been obtained for his daughter, the affidavit says. He is questioning how Ormsby could afford to travel out of the country because she didn't have a job, he said. Thomas was recently given temporary sole legal custody of Sydney, court records show.

"I am constantly worried about my daughter," Thomas said. "I would just ask (Ormsby) to bring her home."

Lee Higgins covers crime and courts for AnnArbor.com. He can be reached by phone at (734) 623-2527 and email at leehiggins@annarbor.com.