New trial for recently sentenced murderer

The intoxicated driver sentenced to 35 years to life in prison for killing a 19-year-old college student during a 2005 highway crash pleaded not guilty yesterday to new charges stemming from an alleged jail house melee while awaiting sentencing on the second-degree murder conviction.

Mark Eugene Henderson, 49, could theoretically face a third strike and mandatory sentence of 25 years to life if convicted in the new case. However, prosecutors haven’t yet decided whether to pursue that option. A decision will likely be made before Henderson’s pretrial conference March 25, said Chief Deputy District Attorney Steve Wagstaffe.

Henderson’s jury trial in the new case was scheduled for April 14 after he declined to waive his right to a speedy hearing.

Henderson picked up the new charges Nov. 29 while awaiting sentencing in the Oct. 1, 2006 death of Rebecca Siebenmorgen.

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 allegedly hoarded by Henderson to make Pruno, an alcoholic beverage made from a variety of food such as bread and fruit.

He is charged with new counts of assault, battery against a custodial officer, drug possession and preventing an officer from performing his duties.

The new case may not add much time to Henderson’s pending prison term but would play a role in how he is classified and housed.

On Feb. 22, Henderson received 15 years to life for the crash that killed Siebenmorgen, a University of California at Santa Cruz student. The term was doubled as a second strike and added another five years for having multiple felonies.

Henderson’s Ford Ranger pickup truck was traveling south when it reportedly drifted into the northbound lane in front of Siebenmorgen’s 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 arrested nearby with a small amount of cocaine in his possession.

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.

Michelle Durand can be reached by e-mail: michelle@smdailyjournal.com or by phone: (650) 344-5200 ext. 102.