Police apologized to the family and placed seven officers on leave while it investigates what went wrong.
MINNEAPOLIS -- With her six children and husband tucked into bed, Yee Moua was watching TV in her living room just after midnight when she heard voices -- faint at first, then louder. Then came the sound of a window shattering.
Moua bolted upstairs, where her husband, Vang Khang, grabbed his shotgun from a closet, knelt and fired a warning shot through his doorway as he heard footsteps coming up the stairs. He let loose with two more blasts. Twenty-two bullets were fired back at him, by the family's count.
Then things suddenly became clear.
"It's the police! Police!" his sons yelled.
Khang, a Hmong immigrant with shaky command of English, set down his gun, raised his hands and was soon on the ground, an officer's boot on his neck.
The gunmen, it turned out, were members of a police SWAT team that had raided the wrong address because of bad information from an informant -- a mistake that some critics say happens all too frequently around the country and gets innocent people killed.
"I have six kids, and only one mistake almost took my kids' life," said Moua, 29. "We will never forget this."
No one was hurt in the raid Sunday, conducted by a task force that fights drugs and gangs, though two police officers were hit by the shotgun blasts and narrowly escaped injury because they were wearing bulletproof vests.
Police apologized to the family and placed the seven officers on leave while it investigates what went wrong.
Such mistakes are a fact of police work, some experts said.
"Does going to the wrong address happen from time to time? Yes," said John Gnagey, executive director of the National Tactical Officers Association in Doylestown, Pa. "Do you corroborate as best you can the information the informant gives you? Absolutely. But still from time to time mistakes are made."
One of the biggest botched raids in recent years happened in Atlanta in 2006, when police killed a 92-year-old woman in a hail of nearly 40 bullets after she fired a shot at what she thought were intruders. Police had gone to her house on a drug raid, but no drugs were found.
Prosecutors said that in obtaining a search warrant, Atlanta police falsely told a judge that an informant had confirmed drug dealing there. The scandal led to a shake-up in the department, two officers pleaded guilty to manslaughter and civil rights charges, and the city faces at least two lawsuits.
Reliable figures on the frequency of erroneous raids are hard to come by. Federal agencies, including the FBI and the U.S. Marshals Service, said they do not keep track.
A study last year by the libertarian Cato Institute said: "Because of shoddy police work, over-reliance on informants, and other problems, each year hundreds of raids are conducted on the wrong addresses, bringing unnecessary terror and frightening confrontation to people never suspected of a crime."
Gnagey disputed the reliability of the research behind those figures, and said it is impossible to know whether they are too high or too low. He said no dependable estimates exist.
"Going to the wrong home is an extreme rarity," said Mark Robbins, a law enforcement professor at Minnesota State University, Mankato. "It's just unfortunate that when it does, it often ends up in violent and even tragic incidents."
In the Minneapolis case, the nature of the tip and precisely what police were looking for were not disclosed; they have not released the search warrant. And it was not clear how far off the mark the informant was in supplying the address.
No charges were brought against Khang, a laid-off machine operator who lives in crime-ridden north Minneapolis. Khang used the shotgun for hunting, said his brother, Dao Khang. In Minnesota, no license is required to own a shotgun.
Khang, who speaks some English but used an interpreter during an interview, said he does not remember hearing any calls of "Police!" until his sons shouted. He said he would never knowingly shoot at officers.
"That's why I reacted the way I did, to protect my family and two sons," said Khang, 34, whose children are ages 3 to 15.
Lt. Amelia Huffman, a police spokeswoman, said the information in the search warrant came from a source who had been reliable in the past.
Huffman said officers who routinely work on drug and gang cases are trained to try to corroborate their information. As for why the process didn't work this time, "that's one of the things the internal investigation will go through in exhaustive detail," she said.
The Hmong are hill people from Laos who aided the CIA during the Vietnam War by fighting the Viet Cong. Hmong refugees began arriving in Minnesota in the late 1970s, and there are perhaps 60,000 Hmong in Minnesota today.
The Khang family is living with relatives until the house gets cleaned up. The raid left six windows broken and walls and ceilings pocked with pellet and bullet holes.
"The whole family is badly shaken and still trying to understand what happened," Moua said.