TAMPA — Shell casings and cell phone data link the man police arrested Tuesday to four recent murders in Seminole Heights, an arrest report shows.

The two-page report released Wednesday offers new details in the evidence against Howell Emanuel Donaldson III, the 24-year-old Tampa resident charged with four counts of first-degree murder.

Investigators found SIG Sauer brand.40 caliber shell casings at all four of the locations where Monica Hoffa, Benjamin Mitchell, Anthony Naiboa and Ronald Felton were found shot to death between Oct. 9 and Nov. 14, the report states.

A forensic analysis found that shell casings from the first three murder scenes were fired from a Glock handgun that Donaldson admitted to purchasing on Oct. 3 at Shooter's World on East Fletcher Avenue in Tampa, the report says. Store receipts showed he picked up the gun four days later, after a mandatory waiting period, along with a 20-round box of SIG Sauer brand .40 caliber ammunition.

BACKSTORY: Seminole Heights slayings: Man, 24, faces four counts of murder

The casings found at the scene of Felton's murder were not available for comparison but had previously been identified as being fired from the same gun as the first three murders, the report says.

It was that gun, according to the report, that Howell gave in a food bag to a coworker at an Ybor City McDonald's on Tuesday afternoon, saying he planned to leave the state. The coworker turned the gun over to a Tampa police officer who was in the restaurant doing paperwork at the time. The Glock had a loaded magazine containing five unfired rounds of .40 caliber ammunition, the report says.

Donaldson told police that "no one except for himself had control of the Glock firearm since his purchase," Detective Austin Hill wrote in the report.

"The gun is what we needed," Tampa Police Chief Brian Dugan at a news conference Wednesday morning. The chief said investigators are "100 percent" confident Donaldson is the killer.

Though they hadn't released it to the public, investigators by that point already knew a critical piece of information, Dugan said: the same gun was used in all four murders. But they didn't know anything about Donaldson's involvement.

Investigators submitted Donaldson's gun for analysis by the Florida Department of Law Enforcement and the Bureau of Alcohol, Tobacco, Firearms and Explosives.

TIMELINE: Key events leading to the arrest in the Seminole Heights slayings

Data obtained from Donaldson's cell phone showed he was in the area of 1300 E Frierson Ave. in Southeast Seminole Heights on dates and times that corresponded with the first three murders. Other cell records showed that within minutes of those first murders, on Oct. 9, 11 and 19, Donaldson's phone was "geographically associated" with an AT&T tower that provided coverage for the areas that include all four murder locations.

Donaldson told police that he "was unfamiliar with the area identified as the Seminole Heights neighborhood, and he did not have any association with anyone in the area," Hill wrote in the report.

During a search of Donaldson's Ford Mustang parked at the McDonald's, investigators found clothing similar to what a man was wearing in surveillance video captured on E Frierson Avenue on Oct. 9 shortly before and after Benjamin Mitchell's murder, the report says. Detectives found what they suspect to be a blood stain on one area of the clothing, the report says.

Standing at a lectern under a sprawling oak tree on the grounds of the Seminole Garden Center in the heart of Seminole Heights, Dugan said Donaldson wasn't on investigators' radar until Tuesday afternoon, when they got the gun and confronted Donaldson when he returned to the McDonald's.

Dugan said he did not believe Donaldson was trying to turn himself in when he gave the gun to a co-worker.

"I don't think he wanted to get caught," the chief said. "He gave it to her for safe-keeping."

After detectives read him his rights and confronted him with the evidence, Donaldson requested an attorney. He was being held without bail Wednesday in the Hillsborough County jail. Court officials said his first appearance in court would be Thursday.

Jail records list Donaldson as a crew chief at McDonald's.

Donaldson was friendly to investigators but did not admit to the killings or offer a motive, according to the chief. Detectives do not believe anyone else was involved in the killings, or that Donaldson has any involvement in any other crimes.

"We were really hoping to find out what was driving him to do this," he said. "We don't have those answers yet. It's an ongoing investigation. We're going to speak to a lot of people now that we know who did this, we're going to have a lot more tips, a lot more information."

Investigators have still not determined Donaldson's connection to the Seminole Heights neighborhood. They also do not yet know how he could have slipped away so quickly after the shootings.

Dugan said he does not believe Donaldson is responsible for any other unsolved murders in Tampa. Detectives will contact police in other jurisdictions where Donaldson has lived to share information in case he could be responsible for other crimes elsewhere.

"As far as I know he has no criminal history," Dugan said.

The arrest, Dugan said, is far from the end of detectives' work on the case. They will now continue to gather evidence to aid prosecutors in getting a conviction.

"Every day at the police department we would meet and discuss how many days it's been since this started, how many days since the last murder, and finally this morning we were able to say that was day one of the healing process," Dugan said. "That's a good feeling, it's a happy day, but I can also tell you it's the beginning of a lot of work ... to get a conviction in this case, because that's when justice truly will be served."

The chief thanked residents of Seminole Heights for their patience and support and the litany of agencies that supported the investigation and stepped up patrols, including the Hillsborough County Sheriff's Office, the Florida Highway Patrol and the St. Petersburg Police Department.

"My heart breaks and grieves for the families of these four individuals that have been murdered and their extended families and friends who have been going through hell for 51 days," Dugan said as several of those grieving loved ones stood behind him. "I can't imagine what it's like as a father to bury a child, and what these people have had to go through is just cruel. I hope this brings this to an end for them, or is at least the first day of the healing process for these families and this community."

Casimar Naiboa, Anthony's father, had criticized the Tampa Police Department in recent days, saying the department wasn't doing enough to catch his son's killer. The elder Naiboa went as far as calling for Buckhorn's resignation.

During Wednesday's news conference, he was among the family members who stood behind the police chief and mayor and thanked them both for their hard work.

"You want to see this person apprehended, and sometimes out of your grief you might say something, like what's going on?" Naiboa said. "The chief understands. We thank everybody for their support. The community, everybody that has stood with us."

Tampa Mayor Bob Buckhorn said at the news conference that Seminole Heights is like a hostage that had finally been freed.

"This has been a chapter that we hoped to never live through, but it's a chapter that told volumes about who we are and what an amazing place this is," Buckhorn said.

Buckhorn got choked up as he talked about the effect on the victims' families.

"These families will never be the same, but we never left 'em," he said. "We told them that we would never leave them. We did our job."

Buckhorn said Donaldson should get the death penalty if convicted.

"I think at the end of this if he is found to be guilty, he should die," the mayor said. "It's that simple."

But for now, he said, the city will try to get back to normal.

"The sun is shining," Buckhorn said. "Tampa's ready to move on and turn that page."

Times staff writers Dan Sullivan and Zachary T. Sampson contributed to this report. Contact Tony Marrero at tmarrero@tampabay.com or 813-226-3374. Follow @tmarrerotimes.

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