Investigators Retool Search For Elusive Metal Collar

Crews are slated to begin excavating parts of the Charles River bed Monday, continuing the search for a massive pipe coupling that failed earlier this month, cutting off potable water to more than two million people in Greater Boston.

Massachusetts Water Resources Authority executive director Fred Laskey Fred Laskey said he hopes this will be the last chapter in the search, which has lasted more than two weeks.

"I don't want to try to predict or give you any odds other than we're frustrated that it's taken this long to find it and we won't give up until we get to the bottom of it," Laskey said.

In addition to searching for the metal coupling, a special support structure also needs to be built, aimed at protecting the newly repaired pipe from the digging.

"We're going to have to build, in a sense, a box that will support the earth on either side of the excavation because it would dangerous to just dig a hole next to the big pipe because it could cause issues that would not be good," Laskey said.

Investigators are trying to streamline their search with radar technology.

"We are now focusing beside the pipe using ground-penetrating radar in which you go and determine what are called 'hot spots' where there is potential for pieces of metal," Laskey said.

It is possible the collar is actually underneath the pipe, says Laskey, which would explain the elusiveness of the highly-sought piece of metal.

"If it is in fact underneath the pipe that's going to pose some other serious challenges, but one step at a time," Laskey said.