A man and a woman shot and killed two men in separate incidents before the pickup truck they were in crashed and a Council Bluffs police officer fatally shot the man, authorities said Thursday.

Officials detailed events that occurred over several days that investigators ultimately determined were connected.

Troy E. Petersen, 28, of Essex, Iowa, was fatally shot Wednesday as he held a gun on his alleged accomplice, April M. Montello-Roberts, 44, of Shenandoah, Iowa. She has been charged with two counts of murder, two counts of attempted murder, and one count each of robbery and burglary. She faces life in prison.

Troy Petersen

Troy Petersen

The two were at least platonic friends and may have been boyfriend and girlfriend, officials said.

Sometime Saturday, police say, 52-year-old Jerrot H. Clark was shot inside his home at 2103 Sixth Ave. by Petersen and Montello-Roberts, who planned to rob him. Clark died from a single gunshot to his head, Council Bluffs Chief Tim Carmody said.

Clark was found at 5:15 p.m. Sunday by officers after a call about a suspicious death.

April Montello-Roberts

April Montello-Roberts

Clark, Petersen and Montello-Roberts all knew each other, Carmody said.

About 2:15 a.m. Wednesday, Pottawattamie County Deputy Sheriff Ryan Olderog spotted a 1997 Dodge Ram pickup truck with its lights off near Country Road L34 and Juniper Road. Petersen fired shots at Olderog as Montello-Roberts drove away, officials said. Olderog lost sight of the truck.

Sometime in the next 25 minutes, officials said, Petersen and Montello-Roberts broke into Steven P. Carlson's home at 270 Yellow Pole Road and fatally shot him. Carlson, 51, died of multiple gunshots, officials said.

Officers spotted Petersen and Montello-Roberts again after they fled from Carlson's home. The two shot at officers again, hitting the SUV driven by Council Bluffs Police Officer Colby McCord as they sped away.

The Dodge Ram crashed in the 1400 block of Indian Hills Road about 2:40 a.m. As officers surrounded the truck, officials said, Petersen told them he was taking Montello-Roberts hostage.

Officers negotiated with Petersen for nearly two hours and convinced him to throw one gun out of the truck. At 4:26 a.m., officials said, Petersen "became more agitated" and pointed a rifle under Montello-Roberts' chin.

A Council Bluffs officer, part of the Emergency Services Team, fired one shot through the windshield of the truck, hitting Petersen in the head. Officers moved in, took Montello-Roberts to a hospital and confirmed that Petersen had died of the gunshot wound.

The officer's name is not yet being released because he still needs to be interviewed, Carmody said. Officials said the officer has been with the department for nine years and has served on the EST team for 5½ years.

The Iowa Division of Criminal Investigation is helping the agencies investigate the shooting.

kevin.cole@owh.com, 402-444-1272