MILTON, Pa. (AP) — Investigators hope tests on a three-ton hunk of concrete will soon solve the 1989 disappearance of a young mother, by determining whether her remains were fed through wood chipper and then entombed in the basement of a Pennsylvania duplex.Sunbury Police Chief Tim Miller announced earlier this month that preliminary results showed the concrete contained wood chips, and he’s waiting to see if they also hold the remains of Barbara Elizabeth Miller.A forensic pathologist is “dissecting the walls, so to speak, piece by piece, hammer-and-chisel type, looking for the smallest of clues,” Miller, no relation to Barbara Miller, said last week. He called it “mere speculation if a wood chipper was or wasn’t used. Obviously the presence of wood chips in a concrete wall is highly suspicious.”An affidavit used to obtain a search warrant for the Milton home disclosed that investigators believe the woman may have been killed by her ex-boyfriend, a onetime Sunbury policeman named Joseph Walter “Mike” Egan.Egan “is and has been the lead suspect in this case since 1989,” the chief wrote in the affidavit.Egan, a Northumberland resident who trims trees for a living, on Friday flatly denied he had anything to do with Barbara Miller’s disappearance.“They’re way off base,” Egan said.The police affidavit said that several people have said that over the years, Egan would talk about driving past his sister’s home in Milton to “visit” his “old lady,” the same building where police seized the massive chunk of cement currently being examined.Egan, 69, who in 1988 was paroled after serving six years in state prison for receiving stolen property and other offenses, a crime he committed as a police officer, reported her missing five days after she disappeared, then moved into her home.The affidavit says Barbara Miller, then 30 years old, had complained to police in the months before she disappeared about Egan, and days before she vanished, told friends she feared for her life.Her teenage son, Eddie Miller Jr., said she and Egan had a fight on June 30, 1989, the night she disappeared, over her plans to attend a friend’s wedding without him. Eddie Miller also recalled that the morning after the wedding, Egan was driving his mother’s car, and the tires were covered with yellow clay that he thought was related to concrete work.“Let me tell you something,” Egan said Friday before ending the brief interview. “It was my car, not her car.”Seventeen years later, a judge declared Barbara Miller dead, but in recent years the Sunbury Daily Item began looking at the case again, and encouraged Tim Miller to investigate after he became police chief last year.“This is most action this case has ever seen, and you can’t ask for more than that,” said Daily Item reporter Francis Scarcella. “There’s no miracle, but we’ve got the attention of people now.”Tim Miller said an informant told him in May that Egan’s sister, Cathy Reitenbach, who in 1989 rented from a judge the Milton home where the concrete slab has been recovered, told the informant in about 1990 that Reitenbach had been one of the last people to see Barbara Miller alive. Reitenbach died in January.The chief found a 2009 report in department files that Barbara Miller’s remains were in the Milton home, but apparently the tip was not pursued. He also located a 2004 report “that Egan put a body inside the wall of a home,” and three people who have said Egan would “get high on cocaine and drive by a home in Milton to ‘check on his old lady,’” Tim Miller wrote in the affidavit.The Milton home’s current owners let investigators into the basement, where they found “highly suspicious construction,” including a concrete floor that was added on, with portions of what appeared to be hand-mixed concrete. A small room in the basement, Tim Miller wrote, “was very peculiar,” with thick concrete walls and an exhaust fan.Another informant, the chief said in the affidavit, told him that Reitenbach’s close friend, Harry Catherman, once told someone that if they did not pay a drug debt, they would “end up just like Barbara Miller did in Cathy’s basement.” Catherman hung up when contacted for comment.In early June, police brought in more than a half-dozen cadaver-smelling dogs, and they all separately alerted that human remains may be present in the basement or in material taken from the basement. During a subsequent weeklong dig, police hauled the massive rectangular chunk of cement from the basement, leading to last week’s announcement that it contains wood chips.Barbara Miller’s former home in Sunbury was also searched, and investigators are keeping quiet about what they found in a metal barrel recovered during an Aug. 10 search of a nearby pond.Barbara Miller was last seen by her friends at about 8 p.m., putting flowers from the wedding into her car. She said she was headed home to change and would meet them later at a bar.___This story has been corrected to show Egan is 69 years old, not 59.