PORT ST. LUCIE, Florida (WPTV) — A man who police said could have become a serial killer is now under arrest for the killing of a 67-year-old Port St. Lucie man last month. Omarion Ivory, 18, is facing charges of first-degree premeditated murder and armed burglary of a dwelling committing battery in the Sept. 8 death of Francis Gennace at his home in the 1000 block of Southeast Albatross Avenue. Gennace’s body, however, wasn’t found until four days later, on Sept. 12, when his employer called police after Gennace hadn’t shown up for work in a few days. At a news conference Thursday, Assistant Police Chief Leo Niemczyk of the Port St. Lucie Police Department said Ivory — who didn’t know Gennace — knocked on the victim’s door on Sept. 8. When Gennace answered, Niemczyk said Ivory hit the 67-year-old with a hammer, then stabbed him to death. “The victim had blunt force trauma to the head and multiple stab wounds. Approximately 45 stab wounds,” Niemczyk said. “Our theory is that he uses [the hammer] to knock the victim out unconscious, then he stabs him.” Ivory was eventually captured 12 days later, on Sept. 20, when an alert Port St. Lucie police detective reviewing surveillance video from Albatross Avenue connected the dots and saw Ivory attempting to break into another home elsewhere in the city. Police quickly responded to that address and took Ivory into custody. He still had the hammer used in Gennace’s killing, Niemczyk said. Niemczyk added that Gennace’s murder was completely random, and police believe that Ivory was preparing to commit a second homicide on a second random victim when he was captured on Sept. 20. “We may have had an undetected serial killer in the works,” Niemczyk said. “This is highly unusual for us. We haven’t seen a lot of these in Port St. Lucie. It was quite concerning.” Niemczyk added that the hammer in Ivory’s possession still had Gennace’s blood on it. “From September 12th to September 20th, this person was roaming the city free?” WPTV News journalist Tyler Hatfield asked Niemczyk at Thursday’s news conference. “Correct. That’s why this is so alarming,” Niemczyk answered, adding that there were no additional homicides in Port St. Lucie during that time frame. According to Niemczyk, Ivory’s family said he has paranoid schizophrenia and has been Baker Acted multiple times in the past, meaning he’s had to undergo a mandatory mental health evaluation when he was believed to be a danger to himself or others. In addition to first-degree murder and armed burglary, Ivory is facing other charges, including burglary of an unoccupied dwelling, grand theft, possession of burglary tools, and loitering or prowling. He’s being held without bond in the St. Lucie County Jail.