Garbage bags strewn across the floor, filthy empty swimming pools and a child's abandoned bicycle: Inside the squalid Las Vegas homes invaded by squatters 

The Las Vegas area is grappling with a squatter problem, fueled by a big inventory of empty houses abandoned by people with deep financial problems when the economy crashed.

Las Vegas police don't have a dedicated squatter unit, but received at least 4,458 squatter-related service calls in Las Vegas and unincorporated Clark County last year, more than double the tally in 2012, according to the Las Vegas Sun. 

City officials recently launched a pilot program to secure abandoned houses with a sheet plastic made of polycarbonate, a supposedly unbreakable alternative to plywood.

The Las Vegas area is grappling with a squatter problem, fueled by a big inventory of empty houses abandoned by people with deep financial problems when the economy crashed. Pictured is the inside of a home where a squatter family left an open box of Pop-Tarts, an iron, a jug of Clorox and what appears to be trash 

Some squatters have used fake rental applications, prompting utilities officials to use paperwork traps to spot fake rental contracts and push squatters out. Code-enforcement officer Matt Meanea (pictured) said squatters used so many identical tactics that he looked online to see if someone posted step-by-step instructions

In Henderson, police and the Greater Las Vegas Association of Realtors created forms for landlords to fill out, to show whether the occupants signed a lease with the actual owners.

Code-enforcement officer Matt Meanea said squatters had used so many identical tactics that he looked online to see if someone posted step-by-step instructions. 

In North Las Vegas, police, code enforcement and utilities officials use paperwork traps to spot fake rental contracts and push squatters out.

'We're working as one to put it together, because without that, we'd be out there spinning our wheels,' said police Officer Scott Vaughn, who leads the department's squatter enforcement.

By all accounts, it's not difficult for squatters to find an abandoned home, and it's easy to draw up a bogus lease. 

Vaughn said he has heard about how-to classes being taught to squatters.

In the first four weeks that North Las Vegas police targeted squatters, they cleared more than 50 houses and made four arrests, Vaughn said. 

Officers have been visiting six to 10 suspected squatter homes per week.

Squatters move to nice and run-down houses, come from 'every walk of life' and target neighborhoods city-wide, according to Vaughn. 

Officers cleared a two-story house in May where a woman and five children lived for eight months, with no water service for the last two months, Vaughn said. 

Some squatter homes can become drug dens, weapons caches and fraud labs, and magnets for child neglect or other criminal activity. Pictured is the inside of a home where a woman and five children had been staying for eight months

An open box of Pop-Tarts, a child's bicycle, furniture, barbecue, mop, water bottles and other items were still inside on a recent visit. 

The woman squabbled with neighbors, sent her kids with buckets to get water from neighbors' hoses, and ran an extension cord to another squatter house next-door for power. 

Southern Nevada's once-battered housing market is recovering from the Great Recession, but it's still ripe for squatting.

About 2.1 per cent of Las Vegas-area homes, or 13,850 properties, are vacant, compared with 1.6 per cent of US homes, according to foreclosure-tracking firm RealtyTrac.

Squatter homes can become drug dens, weapons caches and fraud labs, and magnets for child neglect or other criminal activity, police say.

'We're finding hardcore felons, serious criminals in these houses,' North Las Vegas police Officer Ann Cavaricci said.

Statewide, the state Legislature last year made crimes of housebreaking, or forcibly entering a vacant home to live there or let someone else move in without the owner's consent, and unlawful occupancy, or moving to an empty home without permission.

North Las Vegas City Councilwoman Anita Wood proposed creating a task force in May 2014 and tactics to target squatters. 

Today, if someone tries to get water turned on at a house listed in the city foreclosure registry, utilities officials are alerted to give the application closer scrutiny and try to contact the owner of record.

Water doesn't flow until officials verify the lease is real, utilities director Randy DeVaul said.

Code-enforcement officers, working with police, also compare the landlord's name and signature on an applicant's lease with property records.

Today, if someone tries to get water turned on at a house listed in the city foreclosure registry, utilities officials are alerted to give the application closer scrutiny and try to contact the owner of record. Meanea is pictured outside a vacant home

A former North Las Vegas police chief, Joe Forti, said he didn't see squatters until the mid-1980s. He said fake leases surfaced about 15 years ago.

But it can be difficult to sort through foreclosure, bankruptcy, county recorder and other filings to figure out who owns the home, and track down owners who left the area when the economy collapsed.

'You don't even know which bank or mortgage company owns them anymore,' Forti said.

North Las Vegas was one of the fastest-growing cities in America when the southern Nevada real estate bubble burst. 

State figures say it grew from 165,000 to 230,500 residents from 2004-2014, a more than 70 per cent increase.

When the crash came, the city declared a financial emergency, its bonds fell to junk status and its housing woes became especially severe.

By early 2012, about 31 per cent of US homeowners with mortgages were underwater, meaning their debt outweighed their home value.

In southern Nevada, the figure was 71 per cent, according to listing service Zillow. In North Las Vegas, it was about 81 per cent.

In 2008 and 2009, lenders were filing more than 1,000 default notices and repossessing more than 500 homes in North Las Vegas a month, according to RealtyTrac.

With thousands of empty homes around the valley, a squatters market began to take shape, according to police and real estate pros.

People would break into a house, change the locks, draw up a fake lease to show a police officer or real estate agent if they stopped by, and post a Craigslist ad to 'rent' the property to others. Squatters might meet their 'landlord' at a convenience-store parking lot to pay rent in cash.