The Portland Police Bureau is keeping a list of people arrested most often downtown. The police say that the list, which has grown from 35 to nearly 400, is part of a coordinated strategy to improve livability in Old Town and surrounding neighborhoods by arresting chronic offenders and holding them in jail where they can receive drug, acohol and other treatments to end their criminal behavior. Defense attorneys say that people are being labeled as chronic offenders based on arrests rather than convictions.