As he testified, the rock in question was on the witness stand with a black ring of residue that Burnett said was from a tire.
Burnett’s testimony was accompanied by a series of pictures showing small, rubbery tire-tread fragments recovered from the scene of the crash near Chevy Chase Boulevard.
Shortly before 6 a.m. on Jan. 26, 2005, Alvarez drove his Jeep onto the tracks and doused it with lighter fluid.
But, in what defense attorneys say was a suicidal man’s change of heart, Alvarez left the vehicle moments before the oncoming Metrolink train No. 100 smashed into his car, derailed and hit a parked Union Pacific train and collided with the northbound Metrolink train No. 901 from Glendale.
Alvarez is charged with 11 counts of murder and one count each of train wrecking and arson.
He sat in court Monday dressed in the familiar plaid shirt and beige pants he has worn throughout the trial while scribbling notes and conferring with his attorneys.
After Burnett spent nearly an hour explaining the rubbery substance he found on the rock to defense attorney Thomas Kielty, Deputy Dist. Atty. Cathryn Brougham sought to clarify where that rubber came from.
“Can you say with any certainty that the tire you received samples from were tires that left a mark on the rock?” she asked.
“No,” Burnett answered. “All I can say is that it’s transfer from an automobile tire.”
Burnett’s testimony was a precursor to another defense expert who told jurors that, because of the magnitude of the accident, it was impossible to tell whether Alvarez had set his parking brake while on the tracks, as the prosecution contends.