Jurors also heard from a former exotic dancer who knew Vaughn on the trial's fourth day.
Christopher Vaughn is accused of killing his family.
Thursday, prosecutors continued to try and make their case that Vaughn planned the murder.
The owner of a Plainfield gun shop testified that Vaughn had been at the gun range the evening before his family was shot and killed in 2007. Jurors saw grainy video of Vaughn coming into the range for target practice.
Investigators testified about the murder scene the next day near Channahon, where Kimberly Vaughn and their three children were found dead in the family's SUV.
Defense attorneys contend that Kimberly Vaughn did the shooting, injuring Christopher Vaughn. Prosecutors attempted to knock down that claim with a series of e-mails and blog posts made by Kimberly Vaughn.
The correspondence read by an investigator referred to Kimberly Vaughn's plans for the future -- to travel and volunteer -- and details about how her relationship with Christopher has evolved to appreciate each other's interests.
Prosecutors called a former entertainer from a gentlemen's club to testify. Chrystal Miller testified that five years ago Vaughn told her he was single.
"I remember him specifically stating he had no family life," Miller testified.
Miller also recalled a conversation in which Vaughn said he knew the future. "I remember a comment he made that was strange about knowing the future," she said.
Miller also testified several times that she did not remember details from 2007.
Prosecutors will continue calling witnesses Friday.