The grandparents of the three young daughters of a minister's wife convicted of killing her husband have begun an attempt to adopt the children, a spokeswoman for the Tennessee courts said Monday.

Mary Winkler, 33, was convicted of manslaughter April 19 for shooting her husband, Matthew, at their Church of Christ parsonage last year. Sentencing was set for May 18 but was delayed Monday because of a scheduling conflict with one of the lawyers involved in the case, said court spokeswoman Sue Allison.

"It's unlikely it will be delayed very long," Allison said.

The paternal grandparents of the couple's children have filed a petition in state Chancery Court to terminate Mary Winkler's parental rights and clear the way for adopting the youngsters, Allison said.

Such petitions are confidential, though court hearings will be open to the public, and Allison declined further comment.

The petition was filed in the state's 24th Judicial District and will be heard by Chancellor Ron Harmon of Savannah, Tenn.

Matthew Winkler's parents, Dan and Diane Winkler, have had legal custody of their granddaughters -- ages 2, 7 and 9 -- since shortly after the slaying. The grandparents also have filed a wrongful death lawsuit against Mary Winkler.

Mary Winkler faces three to six years in prison on the manslaughter conviction. She would be eligible for parole after serving a third of the sentence and will receive credit for the five months she already spent in jail.

She could have faced life in prison if convicted as charged with first-degree murder.

Winkler testified at trial that her husband was emotionally and physically abusive and she did not remember pulling the trigger of the shotgun used to kill him.