Authorities say a puppy taking a walk on a Massachusetts beach with its owner uncovered a human bone, which led to the discovery of several others.A man walking his dog found the bones Saturday morning on the Newbury side of Plum Island.Watch NewsCenter 5's reportBill Barrett said his dog Tessa found what appeared to be the remains of a human foot with a sock still on it."We were just out for a walk on the beach with the dog," Barrett said. "We walked over there, and I said no leave it. It was the lower half of the leg with foot still attached, sock on the foot."Investigators discovered more remains later Saturday once the tide had changed, according to police. It was first unclear if the bones were human or animal, but they were confirmed as human remains on Sunday, according to police.  Investigators said Monday the bones were that of a man, but could not offer an age-range or ethnicity.Cadaver dogs were called to the scene Sunday morning during a three-mile search that turned up more remains. Newbury Police Deputy Chief John Lucey said police are still monitoring the beach in case more remains are found as the tides change."There was an effort to organize a sweep of this entire area to make sure there was nothing else, being conducted right now," Lucey said.Police confirmed that the bones found were likely from the lower leg of a human. Barrett said while it was hard to tell, it appeared to him the remains were from an adult male."Could have been a man or a woman, but the sock was big enough that it looked like a guy," Barrett said. Investigators expect processing of the remains to take several days.