BOSTON – Massachusetts State Police divers have finished searching a portion of the Charles River without finding a key section of pipe believed to have broken off during a catastrophic water main rupture over the weekend.

Police ended the search of a 200-yard stretch of the river around 3 p.m. Tuesday.

The Massachusetts Water Resources Authority says the search will continue today as workers dig out two sand bars created when the pipe blew. They’re hoping to find a giant metal coupling weighing up to a ton that investigators believe gave way, leading to a boil-water order for about 2 million Boston-area residents.

The pipe has been fixed and the boil-water order was lifted early Tuesday after clean drinking water again started flowing to 30 cities and towns.