Investigators looking into last week's massive explosion at a fertilizer plant in West, Texas still can't say what caused it.
Teams searched for clues Monday in the 22-foot-deep crater left by the explosion last Wednesday at a fertilizer company in the town of West, Texas.
The search, described as methodical, has yielded very little so far.
The explosion of a stockpile of ammonium nitrate at the plant left 14 dead, mainly volunteer firefighters.
Residents are being allowed to return, but 350 homes can't be occupied.
The town's high school and middle school were too damaged to hold classes, so hundreds of students were sent to class in Waco, about 15 miles away.
Sunday services for a displaced congregation were forced outside, with some seeing each other for the first time since the explosion.
They'll be joined in prayer by the president and first lady at a memorial service for the victims Thursday.
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