As they listened to scratchy recordings and followed along on transcripts, a jury heard two men boasting and laughing about a series of shootings that killed eight people.
Maricopa County prosecutors said the men on the wiretaps are Dale Hausner and Samuel Dieteman.
The recordings, played publicly for the first time Tuesday, allegedly have the two talking almost obsessively about media coverage of the spree that terrorized Phoenix in 2005 and 2006.
"It now brings the total to six," said the man identified as Dieteman, referring to news reports.
"It's higher than that!" said the man identified as Hausner. "What about the guy I (expletive) shot at twice at 27th Avenue in the yard?"
Hausner, 35, is charged with eight counts of first-degree murder and dozens of other charges.
He listened stone-faced as prosecutors and police said the recordings helped prove that he and Dieteman were responsible for the killings. Dieteman has pleaded guilty to two murders and agreed to testify against Hausner.
In all, prosecutors played about a dozen snippets from more than four hours of secret police recordings made on Aug. 3, 2006, just before the two men were arrested at their Mesa apartment.
In one sound segment, the men talked about their individual techniques.
"I try to wait to the last second when somebody's getting near me," said the man identified as Dieteman. "I don't even think I get it level. I just get it to where it's pointed at somebody."
"And bam!" Hausner allegedly interjected.
Testimony began in early October and his trial is expected to last nine months.