Mark Eugene Henderson received 15 years to life

Mark Eugene Henderson, 49, received 15 years to life for the Oct. 1, 2006 death of Rebecca Seibenmorgen, a University of California at Santa Cruz student. Judge Joseph Scott doubled the term as a second strike and added another five years for having multiple felonies. Henderson denied being under the influence of methamphetamine at the time of the crash, instead claiming he was fighting to stay awake. However, following a 16-day trial, a jury deliberated less than two days before convicting Henderson of five felonies including second-degree murder, driving while under the influence causing injury, fleeing the scene of an accident causing death and drug possession. Prosecutor Sean Gallagher said the case rose to the level of murder rather than gross vehicular manslaughter because Henderson’s lengthy criminal and drug record should have taught him better.“It is different than pulling the trigger of a gun, no question about it, but it is hard to come up with something more inherently dangerous than driving a vehicle under the influence,” Gallagher said.Henderson struck his pickup truck head on into Siebenmorgen’s motorcycle, leaving her dead at the scene on Highway 1.Henderson’s Ford Ranger pickup truck was traveling south when it reportedly drifted into the northbound lane in front of an oncoming motorcycle just south of Tunitas Creek Road. Siebenmorgen died from the head-on collision. Henderson fled from the scene, according to the California Highway Patrol, and was found with a small amount of cocaine in his possession.Henderson was arrested near the scene. Witnesses testified he appeared to be weaving before the crash. Prior to this conviction, Henderson was no stranger to incarceration dating from his first offense in 1976 for underage drinking, according to the California Department of Corrections. Between 1982 and 1983 he was convicted of 10 separate driving offenses and in 1983 also received a felony assault conviction. He also violated probation for these offenses five times.His other cases involved domestic violence and drug possession for sale. In 1996, he was sentenced to prison for four years on two drug convictions in Contra Costa County. In 2001, he was convicted of two drug possession charges in Santa Clara County and received eight years and eight months. In 1988, in the same county, he received just more than three years in prison for two possession convictions. Henderson was also convicted of perjury. While awaiting sentencing for Siebenmorgen’s death, Henderson picked up a new case which could count as a third strike with a mandatory sentence of 25 years to life in prison. The District Attorney’s Office has yet to decide if it will pursue that option, Gallagher said. On Nov. 29, according to the District Attorney’s Office, Henderson got into a fight with correctional officers conducting a routine search of jail cells after they saw him trying to flush drugs down his cell toilet. One officer suffered a back injury and a complete cell search turned up a stash of prescription drugs hoarded by Henderson to make Pruno, according to prosecutors.He is now charged with new counts of assault, battery against a custodial officer, drug possession and preventing an officer from performing his duties.