ANAHEIM HILLS (CBSLA) — Authorities said a motorcyclist was killed Thursday evening in a crash on the 91 Freeway.

The crash occurred on the eastbound lane near Gypsum Canyon Road in Anaheim Hills just before the 241 Freeway.

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According to a CHP dispatcher that a SigAlert was issued for the number one and two lanes of the 91 until 11:30 p.m.

Preliminary reports from the scene said the motorcyclist had been racing with a pickup truck.

The CHP did not confirm this but said the cause of the crash was under investigation and that they were looking for another vehicle.

Stu Mundel reporting in Sky9 said the accident was causing a back-up as far as Yorba Linda.

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(credit: CBS)

The investigation was to last several hours, authorities said.

KCAL9’s Nicole Comstock says motorists began calling 911 around 9:15 p.m. to report a motorcyclist traveling at excessive speeds.

The CHP told her they believed the possible street racing scenario after another witness said the motorcyclist was going well above the speed limit and also reported seeing another driver from the right lane cut across lanes leading up to the crash.

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