David Labon Bush spoke in an even, quiet tone as he answered a series of questions at his arraignment Friday morning on a first-degree murder charge. He only raised his voice noticeably when he was asked how he pleads to the charge, which stems from the presumed death of his wife in December 1990.

"Not guilty, your honor," Bush replied to Judge David Park.

Bush has been in custody since Aug. 4, his arrest coming more than 15 years after Lynn Lynette Bush disappeared. He is now charged with first-degree murder and, if convicted, faces the prospect of life imprisonment or the death penalty.

A decision about whether to seek death is due from Natrona County District Attorney Mike Blonigen by Nov. 19.

Bush has been held in jail since early August on $500,000 bond. Kerri Johnson, Bush's attorney, asked Park to consider lowering the bond amount on Friday, pointing out that her client has not left Wyoming in the years since his wife disappeared.

"He's not a threat to the community, your honor," Johnson said.

Blonigen argued in response that the bond is appropriate given the seriousness of the charge Bush faces, the fact he has worked as a long-distance truck driver and his status as a convicted felon.

Park deferred consideration of a reduced bond until next week, when a conference will be held to schedule Bush's trial and set dates for the various motions and hearings that will precede it.

Blonigen said after Friday's hearing that he expects the trial to begin in March or April and to last about three weeks.

Testimony about DNA evidence will likely occupy a significant portion of the trial. Before his wife disappeared in 1990, according to testimony, Bush told a mistress that such evidence is not a "true science."

Since then, DNA has been a central part of many criminal cases, including the 2004 conviction in Natrona County of Dale Wayne Eaton for killing Lisa Marie Kimmell in 1988.

The evidence in Bush's case is complicated by the fact that no biological sample from Lynn Bush was available given her disappearance. To overcome this shortcoming, analysts inferred Lynn Bush's DNA profile by examining samples from various relatives in a process known as reverse paternity testing, according to court documents.

This profile was then matched to DNA from blood samples found inside the Bushes' pickup and on a vodka bottle inside their home, according to documents.

The pickup was parked on Dec. 9, 1990, in the parking lot at 12th and Beverly in front of what used to be Buttrey's grocery store. That day, Bush told police his wife went missing the previous evening and that he found the truck there, its door open and back loaded with day-old groceries.

Police later found possible drops of blood in several locations when they searched the pickup, a Casper police detective testified at Bush's preliminary hearing in late August. A chemical test indicated small amounts of blood over much of the interior, she said, possibly as the result of it having been washed.

Before his wife disappeared, according to testimony, Bush told friends and acquaintances he could commit the "perfect murder" and knew of places where a body would never be found.

In spite of the fact her body has not been found, Judge Michael Patchen, who presided at Bush's preliminary hearing, said "the court is convinced that Lynn is, in fact, dead."