This looks like good ol' detective work from the SPD.
UPDATE at 11:36 AM: Prosecutors have charged Andrew J. Patterson with second-degree murder. "Patterson remains in jail on $2 million bail," says the King County Prosecuting Attorney's office in a statement just issued to reporters. "Prosecutors filed a firearm enhancement with the murder charge, and if convicted as charged, the defendant would face a sentence of 15 to 23 years in prison under state sentencing law. Patterson’s first court appearance will be at arraignment on August 2 at 8:30 a.m. in courtroom 1201 at the King County Courthouse."