@cbsnews: Three police officers were killed in York County, Pennsylvania, last week after officials said they were ambushed by a man accused of stalking his ex-girlfriend. The shooting happened as police were attempting to arrest the suspect, who was hiding in his ex-girlfriend’s home after she and her mother had left for their safety, the York County District Attorney said. “Make no mistake about it, and this I can conclude by all reasonable inferences by all information without speculation,” York County DA Tim Barker said. “Had they arrived home and not Northern Regional Police Department officers arrived, they would have been killed immediately.” CBS News’ Tom Hanson traveled to York County for the latest on the investigation and the growing memorial the community created for the officers who were killed. #pennsylvania #yorkcounty #police #crime