By AMY LINDBLOM and LIZ HARRELSON
Investigators spent most of Friday scouring the asphalt parking lot at the Twain Harte Post Office, looking for clues into a pipe bomb explosion that rattled the mountain community about midnight Thursday.
However, after bombing experts from Calaveras County, the state department of Alcohol, Firearm and Tobacco and the FBI helped Tuolumne County Sheriff's investigators recover debris and in the initial investigation, the case has been turned over to U.S. Postal Service inspectors.
Neither the building nor the lone car with a "for sale" sign on it, parked overnight in the post office parking lot, were damaged, and no one was hurt in the explosion.
"Right now (Friday morning) it looks like it was a fairly small, short, stubby pipe bomb. At first glance, there does not seem to be any similarity between this and the Calaveras pipe bomb, but that will be for the Calaveras County to decide since they investigated the other bombing," said Tuolumne County Sheriff's Sgt. Bob Bogolea.
About 9 p.m. June 30, a pipe bomb exploded at the Calaveras County Government Center on Mountain Ranch Road, blackening a wall at the county's Alcohol and Drug Abuse Program building. Shrapnel from the bomb was embedded into the wall and damaged an air conditioning unit.
That bomb was made from a metal pipe, not plastic, Bogolea said
Calaveras County Bomb Squad officers Clay Hawkins and Phil Ross helped in the Twain Harte investigation Friday.
Some of the larger pieces of PVC pipe were placed in metal containers by state ATF agents.
"By putting the pieces in a sealed container, we can preserve as much of the scent as possible, and from that, we can probably tell what type of powder was used," Bogolea said.
Originally it was thought two pieces of shrapnel pierced the building, but after daybreak Friday, investigators got a better look and concluded the damage was not from Thursday's blast, said Tuolumne County Sheriff Sgt. Chris Harrison.
During Friday's search, the post office was closed to the public, but the building was reopened Saturday.
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