This story has been updated to add new information.

LIMAN ST. LUCIE — Video surveillance and blood on a hammer helped investigators link an 18-year-old man to a September murder in a case that may have involved an “undetected serial killer,” police said Thursday.

PortSt. St. Lucie Police on Wednesday charged Port St. Louis in connection with the Sept. 8 murder of 67-year-old Francis Devon Gennace. Omarion Daitron of the 700 block of Southeast Lansdowne Boulevard in St. Lucie announced the arrest of Ivory.

Ivory is charged with first-degree murder with a gun and armed robbery of a residence following Gennace’s death. He found September 12 at his home in the 1000 block of Southeast Albatross Boulevard.

Deputy Chief Leo Niemczyk said Gennace suffered blunt force trauma to the head and suffered approximately 45 stab wounds.

Gennace didn’t show up for work last seen on September 6 Acting Police Chief Richard Del Toro said. His co-workers contacted police, who went to his home for a welfare check. Gennace reportedly worked at a local auto body business.

Gennace’s wife, Joan, told investigators at the time that she was visiting family in New York and had been there for about a month. She said only she and her husband lived in the home and that she last spoke to him on Sept. 7, according to records.

“When I talked to the victim’s family members, co-workers and people involved in his life, there were no obvious red flags,” Niemczyk said. “No specific suspects have developed. Normally, this type of violent crime… The suspect is known to the victim. And in this case, that wasn’t happening.

Niemczyk called it an “evidentiary case.”

An approximately 4-inch folding knife that family members did not recognize was found next to Gennace’s body, records show.

Police noticed a second knife resting on a pillow in the master bedroom and footprints in Gennace’s blood near the body. The footprints did not match the sandals Gennace was wearing.

Police collected nearly 600 hours of video from homes in the area and eventually located a person depicted in video surveillance walking in the 1000 block of Southeast Albatross Boulevard around 9:18 a.m. Sept. 8.

He was walking towards Gennace’s house and remained out of sight for about 30 minutes before he was seen in separate footage cycling away. At the time, police did not know the identity of the person in the security camera.

Investigators determined that Gennace began missing phone calls from family around 10:45 a.m. on Sept. 8.

‘A completely random move’

A detective reviewing the video on his desk noticed a call on the computer-aided dispatch system on Sept. 20 about a man “who matched the description of the person he observed in the video and was attempting to enter another home,” Niemczyk said.

That home was in the 1900 block of Southeast Lavina Circle, records show. A woman told investigators a “suspicious male” knocked on her door while looking out the window, armed with a hammer.

“Detective (Andrew) Zamfino knew he was a potential suspect when he identified the suspect and heard the other call because we had no idea at that point,” Niemczyk said. “So if that hadn’t happened, I’m not sure where we’d be right now.”

The ivory was found on a bicycle in the area, confirming that he had a hammer in his backpack. Police determined the bike was stolen from a home in the 900 block of Southeast Albatross Boulevard, not far from Gennace’s home.

“In most murders, the suspect and victim know each other. So there is a reason, a reason for killing,” Niemczyk said. “There is nothing in this case. The suspect did not know the victim of the murder and did not know the people whose homes he was trying to break into. So this is a completely random act.”

Police said Ivory said he was visiting a friend but could not give the friend’s name. When asked why he knocked on the door with a hammer in hand, Ivory said he wanted to show the homeowner that he was working on his bike, records show.

Ivory was arrested on charges including loitering and prowling.

Possible ‘undetected serial killer’

Authorities reported that the patterns on Ivory’s shoes were “very similar” to shoe prints at the murder scene.

On October 18, a crime scene official reported that a partial fingerprint on a knife resting on a pillow in the master bedroom at the murder scene came from Ivory.

On Tuesday, investigators learned that Gennace’s DNA was found on the head and handle of the hammer seized in Ivory. Ivory’s DNA was on the handle.

“All accounts lead us to believe that Mr. Ivory was possibly preparing to commit a second murder that day,” Niemczyk said. “We may be after an unidentified serial killer.”

Shown photos from security footage on September 8, Ivory said he was cycling in the area.

“He said he wanted to wait and see how this situation plays out before making a statement,” Niemczyk said.

Fingerprint, shoe print, DNA

Ivory has a juvenile arrest history and a mental health history, Niemczyk said. He said Ivory’s family stated that he was a paranoid schizophrenic.

“We don’t have a confirmed diagnosis, and we also have a history of Baker Acts,” Niemczyk said.

Florida’s Mental Health Act, known as the Baker Act, allows people with mental illness to be held voluntarily or involuntarily in a mental health facility for up to 72 hours if they are deemed a threat to themselves or others.

According to Google.com, Ivory’s listed home address is about 2 miles from the Gennace murder scene and about 6.3 miles from the Southeast Lavina Circle crime scene.

Niemczyk said that in previous Baker Act cases, Ivory “made statements that he was going to kill people.”

“What the victim left at his house were fingerprints, shoe prints and some DNA,” Niemczyk said.

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Will Greenlee He is TCPalm’s breaking news reporter. Follow Will on X @OffTheBeatTweet or reach him at 772-267-7926. Email him at [email protected].

This article first appeared in Treasure Coast Newspapers: Possible ‘undetected serial killer’ arrested in PSL murder case