Los Angeles police said on Friday they were looking for a group of masked thieves who stole an estimated $2 million in diamonds in a backpack from a man whose car they intentionally struck.

The victim told detectives he had left a friend's home in the Los Angeles neighborhood of North Hollywood on Thursday night when his car was hit from behind, Los Angeles Police Department spokesman Richard French said.

According to the man, who was not identified by authorities, another car then blocked his and five or six men jumped out, smashing the driver's side window and trying to grab the backpack, French said.

The victim told police that he struggled with the men, who were wearing dark clothes and ski masks, before losing the backpack when he was struck in the face and head, French said.

French said it was not yet clear why the man was driving around late at night with $2 million in diamonds in a backpack.

The detectives thought it was unusual, French said.

The thieves then fled and are still at large.

Police said there were no suspects in the case, which is being investigated by the LAPD's commercial crimes division and by detectives from the North Hollywood station.

The crime is being investigated as possible work of an organized network, police said.

French said detectives were not releasing any information about the victim while detectives worked the case.

There may be more interest in stealing gold and jewels, French said, because stocks and other investments don't seem to be doing well in the sluggish U.S. economy.

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