DALLAS (CBSDFW.COM) – Calls to the Mid-Cities Medical Clinic on W. Ledbetter in South Dallas now go unanswered. And so do the many questions put to local and federal law enforcement officials about why the facility was targeted.

Early Tuesday morning, Dallas police and agents whose shirts identified them as criminal investigations agents of the Internal Revenue Service carted box after box of documents from the shuttered facility.

Entire file cabinets were loaded onto a dolly and carted off inside a rented U-Haul truck.

A spokesperson for the IRS would only confirm that the agent were on site conducting “official business” and would not name the target of the investigation.

A man approaching the facility shortly after noon said he was a patient. But he quickly hurried away when he saw police, saying, “I don’t want to have nothing to do with it.”

A certificate of occupancy lists the clinic’s owner as Leeroy McCurley.

State medical board records show that a Dr. Leeroy McCurley has been licensed to practice in Texas for more than two decades. CBS 11 attempted to contact Dr. McCurley at his Grand Prairie home, but a neighbor said the doctor moved about a week ago.

Sources say people inside the clinic today were questioned and some arrests were made. One man who didn’t want to be identified came to the clinic looking for a girlfriend who had been arrested.

He said she was taken into custody for an outstanding warrant. Dallas police officials say the matter is a federal investigation. The U.S. Attorney’s office has declined to comment.