Mark Rudolph Seibel

Mark Rudolph Seibel, loving husband, and father, passed away peacefully from brain cancer, on September 11, 2022. He was surrounded by family. He leaves behind his wife of 31 years, his 3 children, his father, his sister, in laws, cousins, nieces, nephews and many friends.

Mark was a Detective II  with the Los Angeles Sheriff’s Department for 32 years. Mark began his career as a bailiff and a patrol deputy. He then moved to the Emergency Operations Bureau in 1999, where he began preparing the sheriff’s department and the State of California for a terrorist attack. After 9-11, it was recognized that he had a gift for leadership, problem solving and recognizing threats which led to him becoming the expert in counter terrorism relating to chemical, biological, radiological, and nuclear threats. He was asked to be a member of the FBI’s Hazardous Materials Response Team. In 2002, he was sworn in as a United States Federal Marshall and joined the Los Angeles Joint Terrorism Task Force. He responded to calls around the nation as a member of the task force.

In 2005, Mark was asked to be an advisor to the Domestic Nuclear Detection Office. This office was tasked with preparing the USA for radiological threats.

 Mark was asked to develop training curriculum by the Los Angeles Sheriff’s Department, the State of California, and the Federal Government. He personally taught thousands of first responders throughout the nation on counter terrorism and chemical, biological, radiological, and nuclear threats.

 Mark developed a new team within the Sheriff’s Department that specifically responded to HazMat calls related to counterterrorism. He was still part of this task force when he passed away on 9-11.

He was tasked with developing counterterrorism plans and implementing them at large events, throughout Southern California, such as the Tournament of Roses, Golden Globes, World Cup Soccer, National Collegiate Football Championships, and the Los Angeles Marathon.  He worked with the Secret Service and the State Department to protect visiting dignitaries. He was known internationally as well. One of his last international assignments was to speak at a training conference for the Japanese Olympics.

His official title was Special Deputy United States Marshall assigned to the Federal Bureau of Investigation’s Hazardous Materials Response Team at the Los Angeles Joint Terrorism Task Force.

Mark was a giant in his field and for good reason. He was intelligent, analytical, driven, and determined. He genuinely wanted this world to be a safer place and was determined to make it so.

His presence was felt just as strongly with his family. He always put the needs of his family first. If he wasn’t working, he was at home.  Family was his priority. He spent countless hours planning trips, playing games, working around the house, and teaching the kids how to do things like swimming and fishing. He loved his family with his whole heart, and he was always thinking of things to do to make them happy. He is with God now and Heaven is a better place because he's there. 

Until I see you again. You will always be my hero.

Mark’s formal Memorial Service will be on his birthday, July 17, 2023, in Huntsville, Alabama. More information will be forthcoming closer to the date.

To send flowers to the family or plant a tree in memory of Mark Rudolph Seibel, please visit our floral store.