Authorities hunting for 73-year-old accused of killing his daughter-in-law The Journal News A manhunt for a 73-year-old diabetic wanted for murder entered its fourth day Thursday as authorities in Rockland County, N.Y., looked for proof that their suspect was even in the state park they were searching. "The woods are too thick for a general sweep," Haverstraw Police Chief Charles Miller said. There are so many places to hide ... [Or] he could have made it to a road and gotten picked up by somebody, and he could be staying elsewhere. Eugene Palmer, of Haverstraw, is accused of killing his estranged daughter-in-law, Tammy Palmer, 39, who lived in a trailer 50 feet from his house, The New York Times reported. His sister, Elaine Babcock, said he stopped by her nearby home Monday morning, gave her money for his property taxes, and then told her that he had killed Palmer before asking her to wait an hour before calling police. But Babcock immediately called 911, The Journal News in New York's Hudson Valley reported. Officers said a separate 911 caller heard three gunshots coming from the home; they found Tammy Palmer, who has two teenage sons with Eugene's son, dead on the ground behind her trailer, NBCNewYork.com reported. Authorities have been combing the thick woods of the 46,000-acre Harriman State Park, which spans Rockland County and Orange County, in their search for Palmer. They believe Palmer is armed with at least one shotgun; at a news conference at the state park on Wednesday, Haverstraw Police Chief Miller said there is also "a lone rifle missing from his house. I don't know if he has that. So far, clues have been sparse in the manhunt for Palmer. On Tuesday, authorities found Palmer's abandoned pickup truck at Harriman State Park, The Journal News reported. And on Wednesday, police said dogs followed his scent to leftovers of a campfire close to the truck in an area of the park known as the Irish Potato Trail, but they lost his scent afterwards, Miller said in Wednesday's news conference. About 30 officers from Haverstraw were looking for Palmer on Wednesday, and authorities from nearby jurisdictions were also participating. The Department of Defense was sending infrared helicopters to track Palmer's body heat, Miller told reporters. His family does not know whether Palmer, who is a diabetic and who suffered a heart attack about a year ago, brought any medication with him. "I'm hopeful he is still alive," Miller said, adding police would like to "hear his side of the story." Part of what makes the search difficult is Palmer's familiarity with the area. According to New York Times, Palmer was known as a loner to his neighbors. He would frequently go into the woods to camp and hunt on his own. Palmer's dislike for his daughter-in-law was obvious to family members. He's been trying to look out for the kids, and her being a mother, didn't want him butting in. But him being a grandfather, thought it was his place, so they started to aggravate and annoy each other," his sister, Babcock, said, according to NBCNewYork.com. She said the feuding also was related to marital problems between Tammy and Palmer's son. Tammy Palmer and John Palmer had been married for about 17 years, John Pannirello, Tammy's father, told The New York Times, but they separated five months ago, and in the past few weeks, they had been in a custody battle over the kids. "He's very coldhearted," Pannirello told The Times of Eugene Palmer. The detective says he won't be surprised if something goes on between us and him, if he has guns with him. I just have a bad, bad feeling. Haverstraw police confirmed on Thursday they were still searching for Palmer, but said they would provide more details on Thursday's efforts later in the day.