PITTSBURGH, Pennsylvania (CNN) -- A highly decorated Green Beret, Staff Sgt. Ryan Maseth died a painful death in Iraq this year. He died not on the battlefield. He died in what should have been one of the safest spots in Iraq: on a U.S. base, in his bathroom.

Ryan Maseth, a 24-year-old Green Beret, died in his shower January 2.

The water pump was not properly grounded, and when he turned on the shower, a jolt of electricity shot through his body and electrocuted him January 2.

The next day, Cheryl Harris was informed of his death. A mother of three sons serving in Iraq, she had feared such news might come one day.

"I did ask exactly, 'How did Ryan die? What happened to him?' And he had told me that Ryan was electrocuted," she said.

Her reaction was disbelief. "I truly couldn't believe he would be electrocuted ... in the shower," she said.

Maseth, 24, was not the first. At least 12 U.S. troops have been electrocuted in Iraq since the start of the war in 2003, according to military and government officials. Watch mom describe horror, heartbreak over son's electrocution »

In fact, the Army issued a bulletin in 2004 warning that electrocution was "growing at an alarming rate." It said five soldiers died that year by electrocution, with improper grounding the likely culprit in each case.

The Army bulletin detailed one soldier's death in a shower -- eerily similar to Maseth's case -- that said he was found "lying on a shower room floor with burn marks on his body."

Maseth's mother says the Army was not immediately forthcoming with details about her son's death.

At one point, she says, the Army told her he had a small appliance with him in the shower on his base, a former palace complex near the Baghdad airport.

"It just created so much doubt, and I know Ryan, I know Ryan, I know how he was trained, I know that he would not have been in a shower with a small appliance and electrocuted himself," she said. Watch "I can't make sense around Ryan's death" »

The Army refused to answer CNN's questions about the case, citing pending litigation by Maseth's family.

Maseth's mother says she pressed the military for answers, eventually uncovering more details about her son's electrocution. The surging current left burn marks across his body, even singeing his hair. Army reports show that he probably suffered a long, painful death.

Fellow soldiers had to break down the door to help, said Patrick Cavanaugh, an attorney for Maseth's parents.

"When they kicked down the door, they smelled burning hair, and they rushed over, saw Sgt. Maseth lying there unconscious, and one of the rescuers himself was shocked electrically and sustained a fairly good jolt because the water and the pipes were still electrified," Cavanaugh said.

Army documents obtained by CNN show that U.S.-paid contractor Kellogg, Brown and Root (KBR) inspected the building and found serious electrical problems a full 11 months before Maseth was electrocuted.

KBR noted "several safety issues concerning the improper grounding of electrical devices." But KBR's contract did not cover "fixing potential hazards." It covered repairing items only after they broke down.

Only after Maseth died did the Army issue an emergency order for KBR to finally fix the electrical problems, and that order was carried out soon thereafter.

In an internal e-mail obtained by CNN, a Navy captain admits that the Army should have known "the extent of the severity of the electrical problems." The e-mail then says the reason the Army did not know was because KBR's inspections were never reviewed by a "qualified government employee."

Larraine McGee is the mother of Sgt. Christopher Everett, another soldier electrocuted in Iraq.

"The impression I got was that this was the first time that it had happened," McGee said.

Her son was cleaning a Humvee on his Iraqi base with a power washer that was not properly grounded in 2005.

"I thought Chris was the first and that because of that, they were going to correct the problem, and it wasn't going to happen again," she said.

When she learned of Maseth's electrocution, she was stunned.

"It makes me very angry, because there is no reason for this to be going on," said McGee.

The electrocution of soldiers is prompting anger in Washington.

"How did this happen?" asked Rep. Henry Waxman, chairman of the House Oversight Committee.

Waxman has called for an investigation. "Why wasn't it corrected when we had the first signs that people were dying from electrocutions?"

In a statement to CNN, the U.S. Department of Defense said it "considers this to be a serious issue and has referred it to the DoD Inspector General's office for action."

The Defense Department said that there are nearly 40,000 structures and housing units in the Iraqi theater and that "we believe there was adequate oversight of the KBR contractors."

"In the past 12 months, KBR performed over 2 million service or work order repairs across the theater," the Defense Department said.

It went on to say that the Pentagon has "no information" that personnel with Defense Contract Management Agency, which handles the KBR contract, was aware of the 2004 Army bulletin or that they "failed to take appropriate action in response to unsafe conditions brought to our attention."

The Defense Department inspector general's office said it could not comment on the new investigation at this time.

KBR declined a CNN interview, but in an e-mail the company said it found "no evidence of a link between the work it has been tasked to perform and the reported electrocutions."

The Defense Contract Management Agency declined to be interviewed, citing the Defense Department investigation.

Harris says she will continue to fight to make sure other soldiers don't die similar deaths.

"I'm not going to sit around quietly," she said. "I want the answers surrounding Ryan's death -- the accountability. And even further, I want to make sure that our troops are taken care of that are left on the ground ... [so] they don't have to wake up and worry about taking a shower and electrocution."

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