The remains of two infants were found Sunday inside plastic boxes under a mobile home in North Texas, and investigators were trying to determine Monday if other bodies might be present, the authorities said. The mobile home is near a field near Rendon, about 15 miles southeast of Fort Worth, where bones of another infant were found in a suitcase last year. Investigators were trying to determine how the three children died. 'We don't know if they were stillborn, late-term abortions or born alive and killed,' said Terry Grisham, a spokesman for the Tarrant County Sheriff's Office. 'We cannot even confirm a crime was committed.' In the morning, deputies questioned the home's former residents, a brother and sister who had lived there for three years before recently moving. They said they knew nothing about the skeletons, Grisham said. The bones were found at 3:30 p.m. Sunday by Justin Southern, the landlord's son, who had been cleaning out the home after the tenants left. Southern noticed that part of the skirting under the porch had been pulled away, the authorities said. In the crawlspace, he found the storage bins. One was wrapped in plastic, the other was not. A forensic anthropologist for the county, Dana Austin, examined the skeletons Monday afternoon but had not determined a cause of death or the age or sex of the infants, said Roger Metcalf, a spokesman for the medical examiner's office. The male child's corpse found in a suitcase in a nearby field on April 9, 2008, was never identified, Metcalf said. Southern also found that body, the authorities said. In that case, the remains were too decomposed for coroners to determine a cause of death. The medical examiner plans to compare the genetic fingerprint of the skeleton in the suitcase to the two newly found skeletons, Metcalf said. Grisham said detectives had found no evidence last year linking the first body to anyone living in the three mobile homes on the property. They are now looking for earlier tenants of the home where the two skeletons were found, he said. The landlord, Rex Southern, lives with his family in one mobile home on the 5-acre property and rents the other two. County workers cut down high weeds and brush and investigators searched for clothing and other clues. Dogs trained to find cadavers were expected to arrive in the evening to check for more bodies. 