all of these people are apple employees. the memorial took place at the company head quarters in cupertino, california. it featured performances by nora jones and coldplay. there were tributes. the service was not open to the public. the stores were closed yesterday so employees could watch the webcast live. another medical expert has taken the stand in the conrad murray trial, accusing the doctor of a long list of violations. saying he was directly responsible for michael jackson's death. the columbia university professor said murray's failure to immediately call 911 was utterly inexcusable. he said murray was clueless when it came to using propofol. he wanted to public to know that the powerful anesthetic was a wonderful drug when properly administered. >> i'm asked the question, are you going to give me the drug that killed michael jackson? i get that question daily.