ABC Channel 23 Screenshot by Chris Matyszczyk/CNET

Cell phones seem to be causing the police increasing unease.

It's quite easy for ordinary people to film officers in the line of duty, and sometimes that duty can seem to be excessively dutiful.

This seems to be the view of Maria Melendez, who says she used her phone to film a case of what appeared to be fatal police brutality, only to have it confiscated without a warrant. Worse, reports are now emerging that some of the footage may have been deleted by the police.

As The New York Times reports, Melendez was leaving the Kern Medical Center in Bakersfield, Calif., in the early hours of May 8 when she witnessed an altercation.

She says she saw six sheriff's deputies hitting a man with a club and kicking him.

She took out her cell phone and told the deputies what she was doing. It's unclear whether she thought this might get them to stop. If that was the case, this doesn't seem to have happened.

She says the man screamed and cried for help for a total of eight minutes. He finally fell silent, and the police then allegedly tied him up and dropped him twice on the ground.

It was only then, Melendez said, that they enacted CPR. David Sal Silva, 33, died less than an hour later.

Melendez said that she and her daughter's boyfriend both filmed what happened. She also said that police confiscated both their phones without a warrant being served.

The sheriff's department disputes this version, insisting that everything was done legally and the phones have been handed to the Bakersfield Police Department.

Melendez and her daughter's boyfriend both said that police officers paid them a visit at their homes and demanded the phones.

The sheriff's office wouldn't discuss the seizures with the Times. (I have embedded very grainy surveillance video of the incident, obtained by ABC Channel 23 in Bakersfield.)

There is no legal gray area with respect to filming the police while they are at work in a public place. The Supreme Court seems very clear that this is legal.

Sadly, though, a recent -- and less violent -- incident in San Diego showed that police don't always seem to respect a citizen's right to use cell phones to record, for example, arrests.

The police's ability to then seize your phone still appears to be under legal debate.

The allegations made by Melendez are serious. They suggest considerable overreaction by the police.

Worse, there are now accusations that some of the cell phone footage has been deleted. A report from the Los Angeles Times says that the FBI has now been called into the investigation.

This move was prompted, said Kern County Sheriff Donny Youngblood, by the fact that one of the two confiscated cell phones seems to have no footage on it at all.

"Our credibility is at stake here," he told the L.A. Times. More witnesses have come forward to support the essence of Melendez's claims that the police were overly zealous.

Youngblood also revealed that, though neither the sergeant nor the six deputies involved were initially suspended, they have now been placed on paid administrative leave. This is partly because they have received e-mail threats.

"They must have gotten rid of one of the videos," Melendez's daughter, Melissa Quair, told the L.A. Times.

Some might conclude from incidents such as the one in Bakersfield that if you're of a mind to film the police and believe wrong has been done, post it to YouTube as soon as you can.

Somehow, once footage is open to the world, it is harder to contradict or dilute its contents.