The images captured on her camera phone led police to the capture of the former principal of a nearby high school. After his arrest on public indecency charges last month, he resigned from a lower school job.
Cell phones that can take pictures are becoming a more common way for victims and other witnesses to help police capture criminals. Because the phones are so portable and always on, it takes only a moment to photograph the face or license plate of someone in the act of a crime.
"I guess I was just quick on my toes," said Johnson, who lives in Alpharetta, about 20 miles north of Atlanta. "I had my hand in my pocket, and rather than hit him and break my phone, I remembered there was a camera."
Camera phones are still a relatively new technology, but already police can point to cases where they have been an important tool.
In New Jersey last year, a 15-year-old boy foiled an abduction attempt when he took pictures of a man trying to lure him into a car. In Pittsburgh last month, several visiting St. John's University basketball players were cleared of a rape accusation after one team member gave investigators his cell phone, which he had used to videotape some of the encounter.
In Japan, an 18-year-old woman took a photo of a 38-year-old man who was fondling her on a commuter train, and police arrested him at the next stop. In Sweden, a convenience store owner took a picture of a robber that was used to help identify and arrest the criminal.
"It's an excellent improvement in technology. Everyone has them with them all the time," said Capt. Robert Rowan of the Clifton, N.J., police department, which investigated the teen's abduction attempt. "You have sort of a crime-fighting device on your person at all times."
On the other hand, camera phones have gotten a bad rap because of reports they've been used in locker rooms and strip clubs to capture nude images that get posted on the Internet, said Alan Reiter, who runs the Web log cameraphonereport.com, which gathers information about wireless photography.
Their real impact will be in the future, when millions of phone users will be able to document any event at any time.
"It's tougher to escape with any open brutality or crimes when people are able to document what you're doing," he said.
In the St. John's case, a woman who claimed she was gang raped by the school's basketball players later confessed she made up the story after players refused to pay her $1,000 for sex.
One of the players took pictures of the incident using a video feature on their phone, which was used to store several 15-second clips, said Lt. Kevin Kraus, who is in charge of the major crimes division for the Pittsburgh police.
"The video we have at this point absolutely contradicts the woman's claim of rape," Kraus said. "It basically exonerated them."
But now the use of that video has raised other questions, he said. Because the woman didn't give permission for the video to be taken, it may violate Pennsylvania's wiretap laws.
"Any information that we as a police agency can recover from these phones can be very beneficial," Kraus said. "But there's always that possibility where other legal issues arise."
The crime-fighting aspects of cell phones aren't limited to photos or video. Wireless company Nextel offers phones for law enforcement agencies that can access the national criminal database.
Those functions could be especially useful for undercover officers who aren't near their patrol cars, said Leon Frazier, vice president of the public sector for Nextel.
"They have this information with them all the time. It gives them a tremendous advantage," he said.
Some officers say picture phones will increasingly help them do their jobs, but they wonder if victims will remember to take snapshots in the heat of the moment.
"I think it will become a reflex — it is for me," said Emily Turrettini, editor for the site picturephoning.com. "People will get used to that."
By Mark Niesse