Portland Police are asking the public’s help identifying a person of interest in the Sept. 10 killing of a 54-year-old homeless man in downtown Portland. Police believe Sunao Thomas Yamada Jr. was killed around 3:20 a.m. near One City Center. He had been seen around that time with a white man, about 25 to 35 years old, with dark, short hair, wearing a black sweatshirt with gray sweatpants or jeans. The sweatshirt had a white logo on the front left chest.