Prosecutors say convicted drug dealer Dustin Honken had the motive, means and opportunity to get rid of the five people he's accused of killing to protect his business 11 years ago.
In closing arguments on Monday, prosecutors also said Honken made false statements, destroyed evidence and acted like a man with plenty to hide in the weeks after three adults and two children disappeared.
"It's behavior that shows a consciousness of guilt," said Tom Miller, the Iowa assistant attorney general assisting federal prosecutors.
Prosecutors say Honken, 35, is responsible for the execution-style slayings of two of his former methamphetamine street dealers, who had agreed to help federal agents investigating Honken's multistate operation. Honken also is accused of killing the girlfriend of one of the informants and her two children.
All five disappeared in 1993, but their bodies were not discovered until 2000, buried in farm fields southwest of Mason City.
Honken, who used his community college chemistry classes to manufacture pounds of pure meth, faces the death penalty if convicted. He already is serving a 27-year term in federal prison in a 1996 drug conviction.
In his four-hour closing argument, Miller retraced the timeline of Honken's drug operation, the disappearance of dealers Greg Nicholson and Terry DeGuess, Nicholson's girlfriend Lori Duncan and her daughters, Amber and Kandi.
Miller acknowledged that the government's case is built on circumstantial evidence, including testimony from the victim's relatives, former associates and statements Honken made to fellow inmates. But he encouraged jurors to connect the dots.
"There is a chain of circumstances from which there is one logical, reasonable conclusion: That Dustin Honken and Angela Johnson committed these murders," Miller said.