Beasley, 53, faces the death penalty for the murders of David Pauley, 51, of Norfolk, Virginia; Ralph Geiger, 56, of Akron, Ohio; and Timothy Kern, 47, of Massillon, Ohio.
He is also charged with the attempted murder of Scott Davis, who answered the Craigslist ad and was shot in the arm while escaping after meeting Beasley and his teenage accomplice Brogan Rafferty. The ad offered a $300-a-week caretaker job in rural Ohio.
Rafferty, 17, was tried as an adult and sentenced to life in prison without parole in November for his role in the deadly scheme. He was 16 years old at the time of the crimes and not eligible for the death penalty.
During Rafferty's trial, jurors heard testimony that the teen helped dig graves for some of the men and was also found in possession of guns and knives stolen from them.
Rafferty testified that he was terrified of the man he had considered a father figure and spiritual adviser after he saw Beasley shoot Geiger in the head execution-style.
Prosecutors say Beasley lured Geiger, his first victim, with the offer of a non-existent caretaker job, killed him, stole his identity and then drew other victims by posting the bogus job on Craigslist.
The attacks were among a series of incidents involving Craigslist and other social media in which people advertising goods for sale or responding to ads have been attacked and killed.
In 2009, a former medical student was accused of killing a masseuse he met through Craigslist. In February, two men in Tennessee were accused of killing a man and a woman for "unfriending" the daughter of one of the suspects on Facebook.
According to court documents, both Rafferty and Davis, the victim who escaped, have been subpoenaed to testify in the trial. Rafferty's attorney told Reuters that a final decision has not been made regarding his testimony.
Jury selection is being held in the Akron Civic Theater because no room in the Summit County courthouse was large enough to accommodate the approximately 200 prospective jurors. Jury selection is expected to last five to six days, with opening statements to begin next week.
(Reporting By Kim Palmer; Editing by Mary Wisniewski, Cynthia Johnston and Dan Grebler)