Tres Peterson, 21, had been living at the home before he and his fiancee broke up.

CANTON In the span of about an hour, Army Reservist Tres Peterson bought a gun, drove to his ex-fiancee's home, fatally shot her, her mother, a family friend and their family dog, then turned the gun on himself.

Police Chief Bruce Lawver said Thursday's triple homicide and suicide at 529 Smith Ave. NW remains under investigation.

"We're seeing no background of any type of violent behavior between the two of them ... It's very shocking to everybody in the community," Lawver said.

Police were called shortly after 1:30 p.m. Thursday to the yellow, two-story home where four people were found dead.

Peterson, 21, of Massillon, had lived there, too, for a couple of months while he was engaged to Cheyenne Calderon, according to police. Her Facebook page said they were engaged Jan. 31. Police said the couple split about a week ago.

Calderon, who was 20, lived there with her 3-year-old son; her mother, Kelly Freshour, 50; Freshour's friend, Timothy Keyser, 70; and Calderon's brother and sister-in-law, who weren't home Thursday at the time of the shootings.

An hour earlier, Peterson had purchased a TP9SA 9mm handgun from a retail store in the Belden Village area that sells firearms, said Detective Bill Adams, lead investigator on the case.

"Tres Peterson, at the time, did nothing wrong," Adams said. "He was a legitimate citizen, and the store conducted the appropriate checks by law, and he passed them. He had no offense tied to an assault or crime of violence."

Adams said the process, which was legal, takes about 45 minutes. Peterson purchased the gun at 12:31 p.m.

See video of Friday's news conference with Canton Police officials:

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At 1:15 p.m., Calderon and a friend of hers saw Peterson walking near the house on Smith. Calderon called her brother and sister-in-law, Lawver said, to warn them. They told Calderon they were almost back home.

They didn't make it in time to save the family.

Shortly after 1:30 p.m., Calderon was in the kitchen with the family's Siberian husky when Peterson walked up to the kitchen door and opened fire, Lawver said.

"The dog ... was right at the door when the door was opened," Lawver said. "He could've just been a target of opportunity that was right there when Peterson came in."

Calderon ran from the kitchen, through the dining room and into a first-floor bedroom, where her mother and Keyser were located, Lawver said.

Peterson chased her, shooting, and killed all three inside the bedroom.

Lawver said Peterson returned to the dining room and killed himself.

During the gunfire, Calderon's friend, Brandon Posey, who was in the living room, grabbed Calderon's son and ran out of the house, the chief said. They escaped unharmed.

Posey called for help, and Calderon's brother and sister-in-law arrived. They were carrying guns and possessed conceal-carry permits, said Capt. David Kurzinsky, who heads the Detective Bureau.

They "went back in to extinguish the situation and to see whether anyone was still alive," Lawver said.

Get more details from Friday's news conference:

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It was too late.

Mayor Thomas Bernabei, speaking at a news conference Friday, categorized the event as "tragic and senseless, and an act, based on what we know at this time, that was totally unpredictable."

"(Calderon's) brother told us that Peterson never demonstrated physical violence or threatening behavior toward her," Lawver said.

Peterson graduated from Washington High School in 2015. His Facebook profile indicates he worked in human resources for the U.S. Army Reserve and as a stocker at Wal-Mart.

Adams said detectives spoke to Peterson's 1st Sergeant at the Army Reserves, where Peterson was an active member with administrative and clerical duties. Peterson was working toward becoming a full-time reservist.

"There were no disciplinary problems. He was a model soldier. He was well-liked, very quiet," Adams said he was told.

Stark County court records show Peterson was charged in December 2015 with telecommunications harassment, but the charge was reduced to disorderly conduct.

Court documents filed in the case say a woman told police Peterson was "constantly harassing" her via telephone and social media for several weeks. She had told Peterson she didn't want him to contact her, and the Massillon Police Department had told him to stop, but he continued. Peterson was fined $100 and ordered to have no contact with the victim. The fine was paid in full in March 2016, and there are no other entries on the docket.

Calderon's grandparents have custody of her child, Lawver said. Police also removed three dogs and two cats from the home.

Autopsies on the victims are expected to be completed Monday.

A gofundme account has been started to cover the costs of the funerals for the three victims and Calderon's son.

On another Facebook profile, this one called "The Tres Peterson Fan Club," a post dated 12:45 p.m. Thursday — about 15 minutes after Peterson purchased the gun — read "Peace out to all my fans love you guys." Another post on the page, from February and from Calderon's profile, read "Can't wait to be Mrs. Tres Peterson" and gave a wedding date of March 25.

See our Facebook page for a video from the news conference.

Staff writer Alison Matas contributed to this report.

Reach Lori at 330-580-8309 or lori.monsewicz@cantonrep.com.

On Twitter: @lmonsewiczREP