With Rapid DNA machines, genetic fingerprinting could become as routine as the old-fashioned kind. But forensic experts see a potential for misuse.

BENSALEM, Pa. — They call it the "magic box." Its trick is speedy, nearly automated processing of DNA.

"It's groundbreaking to have it in the police department," said Detective Glenn Vandegrift of the Bensalem Police Department. "If we can do it, any department in the country can do it."

Bensalem, a suburb in Bucks County, near Philadelphia, is on the leading edge of a revolution in how crimes are solved. For years, when police wanted to learn whether a suspect's DNA matched previously collected crime-scene DNA, they sent a sample to an outside lab, then waited a month or more for results.

But in early 2017, the police booking station in Bensalem became the first in the country to install a Rapid DNA machine, which provides results in 90 minutes, and which police can operate themselves. Since then, a growing number of law enforcement agencies across the country — in Houston, Utah, Delaware — have begun operating similar machines and analyzing DNA on their own.

The science-fiction future, in which police can swiftly identify robbers and murderers from discarded soda cans and cigarette butts, has arrived. In 2017, President Trump signed into law the Rapid DNA Act, which, starting this year, will enable approved police booking stations in several states to connect their Rapid DNA machines to Codis, the national DNA database. Genetic fingerprinting is set to become as routine as the old-fashioned kind.

Law-enforcement officials said that the device had provided leads in hundreds of cases, helping to facilitate arrests and exonerate falsely accused individuals. Members of the Rapid DNA team in the Orange County, Calif., district attorney's office said that some robbers were identified so quickly that they were caught still holding stolen goods. Rapid DNA machines were used to help identify victims of the recent wildfires in Northern California.