Man held without bond in Florida teen's killing
Prosecution may pursue death penalty
David Onstott, center, appears via video at a Tampa, Florida, court hearing on Monday.
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TAMPA, Florida (CNN) -- A Florida judge ordered a convicted sex offender held without bond Monday on first-degree murder charges in the death of 13-year-old Sarah Michelle Lunde.
Hillsborough County Judge Walter R. Heinrich ordered David Onstott held after State's Attorney Mark Ober said Onstott had confessed to killing Lunde. Her partially clothed body was found Saturday in an abandoned fish pond.
Onstott, 36, who appeared in Heinrich's courtroom via video from a detention center, didn't speak during the hearing. He was accompanied by a court-appointed attorney who said Onstott would not enter a plea.
In the days after Sarah's disappearance more than a week ago, authorities questioned Onstott, who was being held by authorities on unrelated charges.
"The defendant subsequently confessed to the crime post-Miranda," said Hillsborough County Sheriff David Gee, referring to the rights suspects must be read for their statements to be admissible in court.
Onstott told police that between midnight and 5 a.m. on April 10, he went to the family's house looking for the victim's mother, who was not at home, Gee said during a news conference Sunday.
The girl, who was alone in the house, invited him inside and became involved in a verbal confrontation with Onstott, which led him to put her in a choke hold, rendering her unconscious "and eventually causing her death," Gee said.
The Hillsborough County medical examiner said Monday that the official cause of Lunde's death might be determined later in the day at the earliest.
By late Monday morning, a partial autopsy had been completed on Lunde's body and additional tests were planned, the medical examiner's office said.
Possible death-penalty case
After Onstott's hearing, Ober said he has yet to decide whether to seek the death penalty in the case. Ober said he and his prosecution team were looking at whether "aggravating factors" in the case outweigh "mitigating factors."
On Sunday, Gee said possible additional charges were being reviewed in the case.
Asked what prompted Onstott's alleged confession, the sheriff said, "I don't know."
Before Gee's announcement, Onstott's attorney denied that his client had anything to do with Sarah's disappearance. Onstott recently ended a relationship with the girl's mother.
Also before the announced charges, Sarah's 17-year-old brother said Onstott was at the family home in Ruskin early last Sunday, hours after his sister was last seen. The brother told police it was the first time he had seen Onstott in months.
Sarah's disappearance prompted a search focused within a three-quarter-mile radius of her mother's home in Ruskin, about 10 miles south of Tampa. More than 20 law enforcement agencies and 22 search-and-rescue teams from throughout Florida had joined the search.
Someone had tried to weigh down the body so it would be hidden underwater, law enforcement sources said.
"It was clear from investigators who were at the scene that whoever put her there went to great effort to conceal her body," Gee said. "And right now, we are asking the public if they would assist us in any articles of clothing that you would see in this area."
Onstott was convicted of sexual battery in 1995 for assaulting a female acquaintance in her home. He served six years in prison and two years on probation on that charge, a sheriff's spokesman said.
He was arrested Tuesday in Apollo Beach, Florida, north of Ruskin, on an unrelated charge of aggravated assault with a deadly weapon after deputies said Onstott threatened a man with a screwdriver during an argument.
He was arraigned Thursday for failing to register as a sex offender and also was being held on a drunken-driving warrant from Michigan.
CNN's Susan Candiotti and Sara Dorsey contributed to this report.