Huge Crowd Expected at Deputy's Memorial

Heading north on Highway 101 on Friday morning? You might want to alter your plans to avoid getting get snarled in traffic related to the public memorial service honoring slain Marin County Sheriff’s Deputy . And if you're attending the service, be sure to leave early.

The memorial takes place at the Marin County Veterans Memorial Auditorium in San Rafael at 11 a.m. About 1,000 people are expected to attend in honor of the Petaluma resident who was  July 19 while off duty as he was assisting a friend with a domestic dispute. A  has been set up to benefit the Mathiesen family.

The auditorium doors open at 9:30 a.m. Friday. San Rafael police said law enforcement and other public safety vehicles will be pouring into the Marin Civic Center area at that time, so expect delays near the Manuel T. Freitas Parkway exit and North San Pedro Road exit on Highway 101.

Traffic on North San Pedro Road, Civic Center Drive, Redwood Highway and Scettrini Drive might be severely impacted during this time period. There will also be heavy foot traffic coming from the Civic Center and crossing Civic Center Drive.  

Traffic could be affected at about 4 p.m. when the service is expected to end as well.

San Rafael police said parking is prohibited from 6 a.m. to 3 p.m. in two locations: both sides of Civic Center Drive starting at Peter Behr Drive and extending south approximately 700 feet; and on McGinnis Parkway from Civic Center Drive to past Embassy Suites Hotel. 

Mathiesen, 49, was shot and killed by Novato resident Thomas Edwin Halloran at a rural residence near Petaluma. A nine-year sheriff's office veteran, Mathiesen went to the residence unarmed and off duty late Monday night after Halloran's ex-girlfriend's mother, Stacey Powers, who was his friend, informed him that Halloran had sent threatening text messages to her 22-year-old daughter.

Halloran showed up at the residence about 20 minutes after Mathiesen arrived. Several people were home at the time -- Powers, her daughter and her son, Anthony Taverna.

When Mathiesen went outside to ask Halloran to leave, Halloran shot the deputy at least twice around 12:12 a.m., according to the Sonoma County Sheriff's Office. Mathiesen died at the scene.

When Halloran then took Powers hostage and tried to force her at gunpoint into a car in the garage, Taverna shot Halloran, who also died at the scene, sheriff's officials said. 

Halloran had a previous conviction for making threats against another ex-girlfriend three years ago, records show.

For more information about the service, go to www.marinsheriff.org.

--Bay City News Service contributed to this report.