The story

It is not possible for authorities to trace the rifle used in this week's shooting at the Holocaust Memorial Museum to the original purchaser, a law enforcement source said Friday.

The source, who was not authorized to speak publicly about the investigation, said the weapon is a Winchester Model 6, .22 caliber rifle -- a type of gun manufactured between 1908 and 1928 -- long before records were kept on gun purchases.

Authorities also were checking to see if the weapon had been used in any other crime, the source said. Read full article »

CNN's Larry Lazo contributed to this report.

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