Updated

Evidence at the murder scene of five Bentler family members points directly to the oldest child, Shawn Bentler, prosecutors said Monday during opening arguments in his trial.

The 23-year-old is accused of fatally shooting his parents and three teenage sisters in the early morning hours of Oct. 14, 2006, at their home in Bonaparte. He's on trial in Van Buren County District Court before Judge Michael R. Mullins.

"There were five brutal slaying that took place at the Bentler house," said Scott Brown, assistant attorney general. "The evidence will overwhelmingly prove that the person that pulled the trigger each and every time was the defendant Shawn Bentler."

Bentler, dressed in a black suit, sat calmly while Brown described in detail the shootings of his parents Michael, 53, and Sandra, 47, and his three teenage sisters, Shayne, 14, Shelby, 15, and Sheena, 17.

Prosecutors will focus on a 911 call made from the Bentler home the night of slayings. The call begins with 14-year-old Shayne saying her older brother was "going to do something," followed by the sound of a gunshot and a scream "Shawn, no!" before the line goes dead.

The call, followed by another not answered by 911 dispatch in time, sent authorities rushing to the Bentler house in Bonaparte at 3:38 a.m. When they arrived, officers found five bodies in what Brown described as a "horrendous" scene. Witnesses testified that at least two of the girls were apparently trying to hide in closets when they were shot, and their mother's body was found slumped over a chair.

"He coldly and systematically slaughtered everybody," Brown told the judge in a whispery, dramatic voice.

Bentler was arrested near his home in Quincy, Ill., on drug- and traffic-related charges just hours after the bodies were found. He has claimed he was home at the time of the shootings.

Prosecutors played the 911 call on Monday, prompting crying in the courtroom. Defense lawyers had tried to suppress the tape, calling its contents hearsay. Prosecutors also will introduce into evidence a pair of socks seized from Bentler while he was in custody. Prosecutors allege the socks contain blood evidence from his mother that links Bentler to the crime scene.

Brown said Shawn Bentler also told his on-and-off-again girlfriend a week before the murders about how much money he stood to inherit if both of his parents died, and asked if she would let him be around their daughter if he had murdered someone. She was expected to testify during the trial, which was expected to last five days.

Bentler waived his right to a jury trial.

The defense plans to call Travis Holder, Bentler's roommate. He is expected to testify that Bentler was at home in Illinois around 1:30 a.m. and that he saw him again at 7 a.m. The defense said Bentler couldn't have traveled to Van Buren County and back in time to commit the crime.

Bentler's attorney David Sallen said his client got along with his family well — that his mother even gave him money and did his laundry — and that he had no motive to kill them.

"He loved his family and was in shock when he learned of their deaths," Sallen said. "This whole ordeal has been extremely rough on him: not only is his family gone, but he is charged as their killer."

Sallen said the state didn't pursue any other leads in the case, even though Bentler's family could have mistaken an intruder for him in the dark house in the morning hours.

"It's clear from the moment of the receipt of the 911 call, and the evidence will show, that the agents of the state of Iowa focused their entire case on Shawn Bentler and no one else," he said.

Van Buren County Deputy Sheriff Robert Caviness began testifying Monday morning. He was the first officer to respond to the 911 call, and he found a rifle in a ditch near the Bentler home that prosecutors believe was used in the slayings. He donned leather gloves to examine and identify the weapon in court.