MINOT - The lead investigator in the killing of Valley City State University student Mindy Morgenstern said Thursday he did not know the exact time of her death, but knew when she last answered her cell phone.

Special Agent Mark Sayler, of the state Bureau of Criminal Investigation, was grilled by an attorney for Moe Gibbs on the investigation into the killing of Morgenstern, 22, of New Salem, last September.

Gibbs, 34, a former Barnes County jailer who lived in the same apartment building as Morgenstern, is being tried on a murder charge.

Jurors were shown evidence Thursday that ranged from knives to a large photo of a cell phone text message.

Investigators believe Morgenstern was strangled and stabbed in her off-campus apartment around 12:30 p.m. Sept. 13, based on her computer use and cell phone calls. Gibbs said he was bringing his wife, Christina, something to drink at work around the time, and his attorneys cited a computer text message from her to back that up.

Gibbs' attorney, Jeff Bredahl, asked Sayler how investigators determined the time of Morgenstern's death. Sayler acknowledged they did not ask the Barnes County coroner to consider body temperature. Bredahl then asked if a missed cell phone call was the sole basis for determining the time of death.

"We determined that from 12:47 p.m. on, she never answered a telephone," Sayler replied.

Asked when she died, Sayler said, "I don't have the exact time." He also said he did not review autopsy reports.

Questioned further by Barnes County prosecutor Brad Cruff, Sayler said officials also estimated the time of death by considering when apartment building residents began smelling Pine-Sol, which had been poured on the body. He said officers also checked computer records and Gibbs' cell phone records.

Sayler said authorities had more than 350 leads in the case and more than 150 items of evidence, about 125 of which were tested at a lab, either the state crime lab or an independent lab in Dallas. He said fingernail clippings and scrapings from Morgenstern's left hand tested positive for Gibbs' DNA.

Bredahl asked Sayler if he was told that male DNA was found under Morgenstern's right-hand fingernails. Sayler said he was not told.

Asked how many leads were unresolved, Sayler said there were "a number," but he could not say how many.

Earlier, a Verizon Wireless company account manager testified that official company records could not verify the time of the text message to Gibbs from his wife.

Her phone shows the message asking him to bring her something to drink was sent at 12:33 p.m. on the day Morgenstern was killed. Verizon account manager John Christy said other calls on Gibbs' phone that day show a time that was off an hour from the company's official records.

Cruff asked Christy if he had any way to verify through the official records that the message asking for a drink was sent at 12:33 p.m., or an hour earlier.

"I don't," Christy answered.

Sayler testified that Christina Judd, whose marriage to Gibbs was annulled April 30, said she first told investigators she sent the text message at 1:33, but later realized it was 12:33.

Bredahl became frustrated with Sayler's answers that he was not familiar with some aspects of the investigation, including the results of DNA tests on cleaning gloves found in Morgenstern's apartment.

"Who would know if not you? Who?" Bredahl asked Sayler at one point.

Sayler said other agents handled parts of the investigation and some reports from an independent lab went directly to attorneys.

Sayler said the hallway in Morgenstern's apartment building was not checked for evidence of biological fluids until 14 days after her death. "We were following up and just looking for what we could," he said, acknowledging that fluids might be degraded by then.

Responding to the defense's questioning about leads that were not pursued, Cruff asked Sayler about some of them - a woman, for example, who told officials she had a vision that "something bad" was going to happen. Sayler said such odd leads were not pursued.

"It's a matter of prioritizing?" Cruff asked. Sayler said it was.

"And you had limited resources?" Cruff asked. Sayler again said yes.