The killings in Arizona began Thursday afternoon, and they continued with alarming frequency.

First there was Steven E. Pitt, a forensic psychiatrist known for his work on high-profile cases like the JonBenet Ramsey investigation. He was shot outside his office in northeast Phoenix.

The next afternoon, Veleria Sharp, 48, a paralegal who had been shot, was seen stumbling down a street and begging for help. When the police followed a trail of blood back to the Scottsdale, Ariz., law firm where she worked, they found Laura Anderson, 49, another paralegal who had been shot. Both women died.

Just hours later, Marshall Levine’s girlfriend found him, a 72-year-old life coach and marriage counselor, dead of two gunshot wounds in his office. That brought the killings in this otherwise relaxed golf and spa hub to four.

By then, ballistic evidence had convinced the authorities that the first two shootings were related. And at about 9:30 p.m. Saturday, they got the most important of more than 100 tips — one that would lead them to Dwight Lamon Jones, a man who had a connection to all of the deceased through a bitter divorce proceeding several years ago.

By Monday morning they felt they had a solid case against Mr. Jones, 56, and they also knew where he was. The police arrived at an Extended Stay America hotel in Scottsdale and surreptitiously began to evacuate guests.

Image Steven Pitt, a forensic psychiatrist, was killed outside his office in Scottsdale, Ariz., on Thursday. Credit... Phoenix Police Department

Mr. Jones figured out what was happening and opened fire on the police. He did not strike any officers. Just after 8 a.m., he was discovered dead of a self-inflicted gunshot wound in his room.

But those were not the only killings.

On Sunday, the police learned of the deaths of a man and a woman at a home in Fountain Hills, about 15 miles east of the other shootings. Though the police later said they had not explicitly linked the deaths of the two — Mary Simmons, 70, and Bryon Thomas, 72 — to Mr. Jones, they said he may have been in the area sometime before the bodies were discovered. That brought the killings they believe he carried out to six in about 96 hours.

“In law enforcement, we don’t have the benefit of saying we were successful when lives are lost,” Sheriff Paul Penzone of Maricopa County said at a news conference, calling Mr. Jones’s actions “the worst of humanity.”

At the same news conference, Rich Slavin, an assistant chief with the Scottsdale Police Department, tied the first four deaths together. Mr. Jones, he said, had gone through “a divorce situation” eight or nine years ago, in which his now ex-wife, Connie Jones, had retained a lawyer at the firm where the paralegals were killed. As part of his divorce proceeding, Mr. Jones was also required to see Dr. Pitt; and his son was required to see a doctor who had used the office space Dr. Levine happened to be occupying the day Mr. Jones shot him.

“We started to see that Mr. Jones was visiting them in an effort to right some wrong,” Chief Slavin said, adding that the suspect had probably intended to kill Ms. Jones’s lawyer.

Image Dwight Lamon Jones, a suspect in six killings in Arizona, fatally shot himself on Monday morning, the police said. Credit... Scottsdale Police Department

“She wasn’t present in that law firm that day,” Chief Slavin continued. “Unfortunately, two employees were.”

In a statement, Ms. Jones said she was “deeply saddened by the tragedy caused by my ex-husband,” who she called “a very emotionally disturbed person.”

She also said her husband, a retired Phoenix police detective, recognized the connection between the divorce and the three crime scenes and he notified the police Saturday night, around the time the police say they got the crucial tip.

“Personally, I have feared for my safety for the past nine years,” she said. “I cannot express the emotions I feel for the innocent families touched by this senseless violence.”

A Facebook page belonging to a “Dwight Jones” contains posts from May in which he leveled several accusations against Ms. Jones and called her a liar. The authorities said he had posted YouTube videos, which, as of Monday, appeared to have been removed.

Chief Slavin said Mr. Jones had been arrested around 2008 or 2009 on domestic violence charges alleging that he mistreated his wife and a child. He also said Mr. Jones had been residing at Extended Stay hotels for the past nine years.

Ms. Jones was far from the only person who was on edge over the past several days. The killings, which had not appeared to be random, worried those in the medical and legal professions and prompted the police to blanket Maricopa County with officers who provided security for people who may have been at risk.

“I personally fielded a lot of questions from those groups because they were concerned,” Sgt. Ben Hoster of the Scottsdale Police Department said. Among their inquiries, he said: “Should we go to work on Monday?”

At a breakfast restaurant just steps away from the hotel where Mr. Jones shot himself, Peter Verros, the restaurant’s owner, noted how uncommon violence was in the area.

“This is a suburb,” Mr. Verros, 40, said. “You’re not used to something like this — a four-, six-person murder spree in Scottsdale? Holy cow!”

When asked Monday about the killer’s motive, Chief Slavin said it was impossible to totally understand.

“Taking the lives of innocent people,” Phoenix Police Chief Jeri Williams said, “should never make any sense.”