TUCSON, Ariz (Reuters) - When the heavy battering started to buckle the front door of her new home in Tucson, Maria remained frozen to the spot with fear.
As her family scattered to hide in the bedrooms, bathroom and kitchen, masked men toting guns and dressed in flack jackets stormed into the living room shouting "Police! Everyone on the floor!"
Her cheek pressed to the ground, she watched as the men fanned out through the comfortable suburban house, pistol whipping her brother-in-law and shouting, "Where are the guns and the drugs?"
"I raised my head and saw his black boots ... It was then I realized they weren't police at all," she recalled, speaking on condition of anonymity.
Maria, who has no connection to the criminal underworld, is among scores of law-abiding Tucson residents caught up in a wave of violent so-called home invasions, most of them linked to the lucrative trade in drugs smuggled from Mexico. Maria had bought the house weeks before and the gunmen believed drug traffickers were using it.
The desert city is less than two hour's drive from the Mexico border. It lies on a crossroads for the multimillion dollar trade in drugs headed north to market across the United States from Mexico, as well as guns and hot money proceeds headed south to the cartels.
Five years ago, police say home invasions were virtually unheard of in Tucson. Now the crimes run at three to four a week, as criminals go after the profits of the illicit trade in marijuana, black-tar heroin, cocaine and methamphetamine through the city.
"We've always dealt with those in business establishments, banks and convenience stores, it was very unusual to see them in houses," Roberto A. Villasenor, Tucson's assistant chief of police said of the recent trend. "The home was seen as a safe spot."
Curbing drug violence is a top concern for the government in Mexico, where rival cartels murdered 6,300 people last year as they battled the authorities and each other for control of lucrative smuggling corridors to the United States.
It is also high on the U.S. agenda as authorities seek to stop cartel-related crimes such as kidnappings, home invasions and gangland-style slayings from bleeding over the porous U.S. border and taking hold here.
A year ago, Tucson police department set up a special unit to target the rising number of home invasions. Since then, the officers have investigated at least 173 cases scattered across the city, three-quarters of them tied to the drug trade, investigators say.
The assailants -- typically teams of two to six people -- frequently dress in tactical gear and identify themselves as police officers, Drug Enforcement Administration agents or SWAT team members as they burst into houses to steal drugs, cash or guns.
"Demographics mean nothing when it comes to home invasions. We see (them) in some of the richest, most wealthy parts of town, and also in some of the most downtrodden, completely poor areas," said Detective Sergeant David Azuelo, who runs the home invasion unit.
While most raids target the drug trade, some have branched out and gone after students and other law-abiding residents, Azuelo said. Others assault families who just happen to live in a house that was once used to deal drugs, or simply because the attackers got the wrong address.
"Just imagine, you're sitting at home relaxing, watching TV. All of a sudden your door bursts open, people are screaming and yelling, they're pointing guns at you, they may be hitting your family members," he said. "I can't imagine many crimes that are worse than that."
Last month, U.S. Homeland Security Secretary Janet Napolitano announced a $184-million plan to crack down on the smuggling of narcotics, guns and money by criminal gangs that threaten security on both sides of the border.
The plan also allocated $59 million to help local law enforcement tackle border-related crime -- a lifeline welcomed by Tucson police.
"We are looking to take advantage of any of those funds that we can, because we have needs here," assistant chief Villasenor told Reuters in a recent interview.
He said the home invasion unit, which currently has five detectives, needed more officers, as well as additional crime-scene technicians to catch the criminals, whom police say are a mostly local street gang members and a "hodgepodge" of criminal opportunists.
Villasenor would also welcome better surveillance equipment to help officers nab the increasingly tech-savvy criminals, who often hard to trace disposable cell phones with prepaid minutes to plan and carry out their crimes.
Putting the criminals behind bars would also be an important step to helping victims like Maria overcome the trauma of the violent raid on her home.
"We haven't slept since it happened," she said as she perched on the edge of the couch in her living room, her eyes brimming with tears. "I keep wondering if they will be back."
Editing by Cynthia Osterman