OAKLAND (KPIX 5) — The Oakland Police Department held a memorial Thursday to mark the ten-year anniversary of the death of four officers, shot by a wanted felon.

Police officers gathered at Saint Benedict Catholic Church to remember the tragic day that left Oakland and the Bay Area in mourning.

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On March 21, 2009, Officer John Hege and Sergeant Mark Dunakin were shot during a traffic stop of a wanted felon linked to a series of violent rapes. Dunakin was pronounced dead at the scene while Hege died of his injuries three days later.

SWAT team members Sergeant Ervin Romans and Daniel Sakai were killed by the same suspect later that day while storming an apartment looking for him. Their fellow officers then shot and killed the suspect.

At the time, it was the deadliest attack U.S. law enforcement since the September 11 attacks and the deadliest in California since 1970.

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“Our fallen heroes are never forgotten,” said Oakland Police Chief Anne Kirkpatrick.

“This is just a stark reminder to us what a dangerous job our police officers have and that as a city we mourn every loss of life,” said Oakland Mayor Libby Schaaf.

The city holds a memorial for the officers every year, but for many of their comrades, time has not healed the pain even after 10 years.

“We have officers who just couldn’t come to work today,” said Kirkpatrick. “It’s too hard on them.”

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OPD made sure that all beats around the city were covered during Thursday’s memorial. Many of the attendees came in on their days off, others made sure that the shifts were covered.