SACRAMENTO, Calif. -- One of the most painful weeks in the history of the Sacramento County Sheriff's Department will come to an end Wednesday at a memorial service for the two deputies killed in last week's helicopter crash.

The church where Wednesday's service will be held is getting ready to accommodate thousands of mourners for the helicopter pilot, 36-year-old Joseph Kievernagel (pictured, left), and 29-year-old Kevin Blount (pictured, below), an observer. Another deputy who was in the helicopter, Eric Henrikson, remains in critical condition at Mercy San Juan Medical Center.

Inside St. John Vianney Catholic Church, in Rancho Cordova, workers were finishing up some last-minute cleaning.

Flowers and cameras are already in place inside the church. Outside, chairs have been put up all throughout the grounds, and a plasma television has been set up to carry the service.

The service is expected to be standing room only as thousand of officers from all over the state are scheduled to attend and pay their respects.

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Live: Memorial Service Coverage

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Some are already expressing their emotions on a special Web site. The sheriff's department K-9 unit and air operations work very closely. So, it's on the K-9 unit's Web site where people are posting tributes to the fallen officers.

The Web site includes a guest book section, and tributes are coming in from around the world, including Switzerland and Newfoundland.

To sign the department's guest book, CLICK HERE.

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Video: Deputies' Tributes

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On Friday, the National Transportation Safety Board announced that catastrophic internal engine failure caused the crash.

The helicopter -- a Eurocopter EC 120 -- went down Wednesday night on a hillside near Lake Natoma. NTSB officials said the helicopter engine's internal turbine blades disintegrated in flight.

Pockmarks on the engine, coupled with soot scars left by the red hot metal hitting the tailpipe, was clear evidence of mechanical error, according to an NTSB official.