Most of the evidence used to convict David Russell Hosier was obtained improperly and shouldn't have been allowed, Assistant Public Defender Craig A. Johnston told the Missouri Supreme Court on Thursday morning.
Johnston argued Jefferson City police didn't have enough evidence that Hosier, now 59, was involved in killing Angela Gilpin, 45, and her estranged husband, Rodney Gilpin, 61, in the early morning hours of Sept. 28, 2009 - so they shouldn't have been given a judge's approval to track Hosier's cellphone.
"The first point involves cellphone tracking of the defendant, finding his location and, ultimately, finding what the state portrayed to be the murder weapon," Johnston said during oral arguments in the appeal of Hosier's first-degree murder conviction and death sentence for killing Angela. "What the real issue is, does the 4th Amendment prohibit this?
"Does the 4th Amendment require a warrant, based on probable cause, before you can track somebody 24/7 for a 60-day period by pinging their cellphone?"
That amendment protects people from "unreasonable searches and seizures" and requires that warrants can be issued only after a showing of probable cause, "particularly describing the place to be searched, and the persons or things to be seized."
Johnston urged the seven-member high court to agree with his view that people "do have an expectation of privacy from law enforcement tracking your every movement" - and that the Jefferson City officials investigating the Gilpin murders might have had suspicions and guesses about Hosier's involvement, but not enough information for a formal warrant.
"The cellphone "pinging' order that was secured in this case clearly was not supported by probable cause," he said. "All the affidavit alleged was, other than the defendant's phone number, "David R. Hosier has been identified as the primary suspect in the homicide investigation.' No facts."
Without their "unconstitutional search - the tracking of the defendant - they never would have located him," Johnston said and, therefore, never would have been able to search his car and find the hand-built STEN submachine gun believed to have been used in the murders.
He acknowledged that other U.S. courts are split on this issue.
But Assistant Attorney General Gregory L. Barnes said Hosier didn't have the privacy expectations Johnston wants the court to find.
"This is a case in which the defendant bought the cellphone, chose to bring the cellphone with him and chose to leave the phone in the "on' position - where it was transmitting signals to a business-contractor," he said.
Barnes noted there also is no expectation of privacy involving financial records or ATM withdrawals, and that pinging a cellphone to find its location is no different from looking for a "purple car" traveling on a highway.
Johnston also asked the Supreme Court to erase the conviction and death sentence, because Cole County Prosecutor Mark Richardson showed the jurors pictures of numerous weapons found in Hosier's car, apartment and storage unit - but that had no connection to the Gilpin murders.
Barnes countered those pictures didn't prejudice the jury against Hosier - a convicted felon who had no legal right to have weapons - because he had guns "with him in the car, and he took a bulletproof vest, and he's fleeing a murder scene."
The Gilpins were separated, but working to reconcile their 21-year marriage, when their bodies were found about 3:30 a.m. in the doorway of Angela's West High Street apartment.
Angela had dated Hosier, and stayed in his nearby apartment, during that separation - and, prosecutors argued during last year's trial, Hosier became angry and had told some friends that, if she "would not come back with him," then he "would put a stop to it somehow."
Last year's trial only involved Angela's murder. Hosier currently is in the Potosi Correctional Center, facing execution for his death sentence in the case.
He also remains charged with Rodney's murder, but no trial has been scheduled.
Richardson said last year he would decide later whether to stage that separate trial, and - when asked last week if there had been any change in that plan - said: "I will not be making a comment while the present case is on appeal."
Richardson and Barbara Eichholz, Angela's mother, attended Thursday's Supreme Court hearing but didn't comment about it afterward.