HOUSTON -- Tonight, Local 2 Investigates goes inside Houston-area pain clinics. Are some of these clinics really "pill mills" in disguise? We uncover just what kind of medical care is really going on.

Last night, we exposed how drug agents say it's too easy to get addictive prescription drugs inside some Houston pain clinics.

Tonight, our hidden cameras go inside those clinics popping up all over town to tell you the inside story.

Investigative Reporter Stephen Dean shows you just how they work and why police say they're putting dangerous drugs on the street.

On hidden camera, a clinic worker asks, "Got any back pain?"

"Yes, ma'am," a patient replies. "On my shoulder, too."

Drug addicts can describe any kind of pain, even if they're vague.

Clinic worker: "Have any anxiety?"

Patient: "I do have anxiety. I'm under a lot of stress."

Then, a pain clinic worker realizes our undercover patient, a police officer, left a bunch of paperwork blank.

Clinic worker: "You didn't even fill it out."

Patient: "I didn't see it. I'm sorry."

Never mind that. The clinic still fixed him up with dozens of pills. They even asked what all he wanted.

Clinic worker: "Put Lorcets on there."

Another clinic worker: "How you spell that?"

Once they cleared that up, within minutes C&T Medical on Beechnut in southwest Houston gave our officer three powerful prescriptions, including Lorcet (or hydrocodone).

We went back in, and workers would only tell us nothing illegal is going on here.

"The person filling out the form couldn't even spell Lorcet," said Local 2 investigative reporter Stephen Dean. "So I need to talk to somebody."

"Y'all need to leave until then," said a clinic employee.

"I want to ask the right person," said Dean.

"Get that thing out of my face. Y'all need to leave," said the employee.

We talked with a Houston father with a son addicted to prescription drugs.

"It's just so simple," the father said. "I mean anybody can walk in and get pain medication."

He found out his son was addicted, with only a stack of pain clinic fliers to show for it.

Most clinics pass out ads for their competitors, guiding drug users to other clinics to score more pills on the same day.

It's tearing this Jewish family apart.

"I compared him to a victim of the Holocaust," the father said. "He's so thin and stripped out that, I mean literally, his bones are showing. He's so thin now."

The dad knows other sons and daughters are suffering because of what our hidden cameras found in clinic after clinic all over town.

"They buy them, get large quantities of them, and then the ones that they don't need, or can't use them right away, they'll sell them to somebody else," he said. "That's how they pay to support the habit."

All of the clinics we visited gave us prescriptions for with the same cocktail of hydrocodone, Xanax, and Soma -- even if we didn't ask for it.

Clinic worker: "So you want Lorcet and uh...?"

Patient: "Soma."

Clinic worker: "Soma. What about Xanax?"

Patient: "I'm sorry?"

Clinic worker: "Do you want Xanax, too?"

Patient:" Xanax?"

Clinic worker: "For anxiety. Do you want medicine for anxiety, too?"

Patient: "Yeah, 'Z', yeah."

Xanax, or "Z-bars," are popular in middle and high school, and undercover Houston Police narcotics officer John Kowal says that's where a lot of these pills end up.

"I don't really think they care about what the ultimate consumer of these drugs are or where they go, whether it's school kids here in Texas or Louisiana," Kowal said.

Kowal believes there are 300 to 400 pill clinics in Houston. The officer who visited the clinics with a hidden camera is from a different police department. He had a stack of flyers, so we went from clinic to clinic, grabbing a new prescription every hour or so.

"These clinics are highly mobile," said Kowal. "They'll sign a short-term lease in a strip center. The staff will work for that particular clinic for a few months and go and move on to another clinic."

All the clinics only take cash, and police say some of the doctors are raking in $4,000 a month from many different clinics at the same time. So what kind of care does that money buy?

Clinic doctor: "Did you go to the doctor?"

That's a doctor asking if our undercover patient had seen a doctor for his pain. But before she gives him narcotics, she's supposed to give a thorough examination, right? Well, she doesn't even take his blood pressure.

But she has to write something on his chart.

Clinic doctor: "What's your regular blood pressure then?"

She takes his word for it, then prescribes the same three-drug cocktail, even though she warned him it's addictive. We couldn't verify this doctor's name. Her prescription was written in the name of a male doctor.

"She wrote this prescription under Dr. Brown's name, but she's obviously not Dr. Frederick Brown," Dean asks an employee at Global Group of Doctors on Harwin in southwest Houston. "I need to speak with her or whoever runs the office."

But then the lights went out in the office.

"Is there a doctor in the house?" Dean asked. "How can I talk to who's in charge here?"

The employees left the office without responding.

"They're (pain clinics) in business for the sole reason of providing these drugs for a non-legitimate medical purpose," said Kowal.

Houston police say many clinic owners know exactly what records to keep so they can avoid arrest and stay within the law.

Thursday morning on Local 2 News at 6:50 a.m., we'll look at a new law coming to track multiple prescriptions, and how police say clinics have been doctoring paperwork to make visits from addicts seem legitimate.