Federal surveillance cameras were rolling in a Michigan medical clinic’s parking lot earlier this year as two little girls were brought, separately, in for alleged genital mutilation procedures, according to The Detroit News.

But it wasn’t until three weeks later, apparently, that investigators on the case – the first in U.S. federal courts dealing with female genital mutilation -- analyzed the clips and realized what had been captured on the video, the newspaper said.

The video shows Dr. Fakhruddin Attar, owner of the Burhani Medical Clinic, his wife, Farida Attar, who is the clinic manager, and another doctor, Jumana Nagarwala, arriving at the facility in the early evening of Feb. 3, minutes before the two girls – age 7 – arrived separately with an adult.

The video is expected to be a key piece of evidence in the federal government’s effort to obtain convictions against the Attars and Nagarwala, the newspaper said. They face charges of female genital mutilation, conspiring to commit female genital mutilation and trying to cover up the crimes.

They could be sentenced to life in prison if they are found guilty of transporting minors – who traveled from Minnesota – for the surgery, the newspaper reported.

Nagarwala and the Attars deny the charges. Nagarwala says that she removed mucus membrane from the girls’ genitalia. Attar said he did not have any knowledge of any illegal procedures performed at his clinic.

“It’s wildly hypocritical to say a horrific event happened, yet they had a camera and didn’t stop it,” the newspaper quoted Mary Chartier, attorney for Attar, as saying. “I have wild concerns about the government alleging female genital mutilation happened at the clinic yet sat back and watched it happen.”

The girls appear to belong to Dawoodi Bohra, a small Shia Muslim sect based in India.

Agents installed the camera on a utility pole Jan. 25, after they learned about possible criminal activity at the clinic, the newspaper said, citing unnamed sources.

Two of the agencies involved in the case, the U.S. Attorney’s Office and FBI, declined comment, according to the publication.

Court records indicate that investigators were not watching the footage at the time the camera was capturing the doctors arriving, followed by the girls being brought to the clinic. There is also no suggestion in the documents that investigators had any knowledge that procedures were going to take place that evening.

On Wednesday afternoon, U.S. District Court Judge Elizabeth Stafford, sitting in Detroit, denied the Attars' request to be released on bond, court case manager Marlena Williams told Fox News. Nagarwala is being held without bond until her hearing on June 27.

The Detroit News noted that with a surveillance camera in an area where someone would not have an expectation of privacy, investigators could operate without a warrant.

“You are allowed to use it under the law to see what would otherwise be exposed to somebody if they were on a utility pole, like a utility worker,” said former Assistant U.S. Attorney Louis Gabel, who is not on the case, according to the newspaper.

A criminal complaint filed after the discovery of the footage provides a timeline of comings and goings at the clinic on the evening of Feb. 3. The video showed Nagarwala arriving at the parking lot at 6:09 p.m., followed by clinic owner Attar three minutes later. Then they both enter the clinic. Shortly after, Farida Attar meets them at the clinic.

The first 7-year-old girl, in the company of a woman, arrives at 6:25, and leaves nearly 20 minutes later. The complaint says the girl and woman left after Nagarwala allegedly performed the genital mutilation.

The complaint says that the girl told investigators later that she went to Michigan as part of a “special girls’ trip” and went to the clinic to “get the germs out.” The child told investigators, the News reported, that Nagarwala pinched her in the area where “goes pee.”

A medical exam revealed that both girls' genitalia had scar tissues and lacerations, according to government allegations.

The second child arrived at the clinic shortly after the first left. She too stayed inside for about 20 minutes before leaving with a woman.

That girl also singled out Nagarwala as the doctor she went to see. In the visit to the clinic, the girl said, according to court records, she got a shot that was painful.

Almost immediately after the second girl left the clinic, the doctors and the clinic manager left.

FBI agents secured a court order that gave them access to Nagarwala’s phone records, which showed several calls to Minnesota. An FBI agent said in a court document that the Minnesota number was traced back to the family of the first girl.

While in Michigan, both girls stayed at hotels near the clinic.

Authorities believe there are many more victims.