More than 100 banks use Zelle, a popular mobile banking app that transfers money in a flash.
But some say that convenience comes at a cost: consumers across the country say fraudulent transfers are draining their bank accounts.
Enter an email or phone number, push send, and off goes the money in a snap.
But the features that make Zelle so appealing to consumers also make it irresistible to hackers, experts say, who are in and out before users know what hit them.
An app that self-described starving artist Dave Fogler says he learned about too late, after watching $3,900 vanish from his Bank of America account.
“I never heard of it until I got hacked,” Fogler said.
A fraudulent transfer, Fogler said, carried out by someone who went by a generic name he’d never heard: Herman Wong, he said.
"He emailed it to himself," Fogler said.
He called Bank of America right away, Fogler said filed a police report, and--at the bank’s recommendation--had his computer scanned for viruses.
That was after Bank of America denied his claim--twice--and pointed the finger at him.
“They emailed me a letter saying that they believe I gave my password to somebody and they’re denying it," Fogler said.
The same kind of treatment Veta Slaton says she got at Chase Bank.
"Where’s my money," she demanded.
The Chicago great-grandmother, living on a fixed income, says she caught two confusing transfers in real time and asked the bank for help.
"I said something is goin’ on," she recalled.
In all, $1,400--gone.
"I’m sittin’ there cryin’," Slaton said. "This is my whole check for the month."
When Slaton asked Chase to investigate, she says the bank tried to pin it on her.
"They’re sayin’ 'well do you have a computer?' No I don’t have a computer," she said. "'Who’s in your house?' Nobody lives with me."
Her claim was also denied.
"It’s in orbit somewhere, but I did it," she said. "So it’s just floatin’ around in the air?"
Back in June of 2017, Zelle was launched, and is now owned by, seven major banks--including Chase and Bank of America.
The thing that sets it apart from its competitors, experts say--its speed--may also be what gives thieves such a head start over law enforcement.
NBC 5 Responds found a number of similar complaints nationwide--including a case in Naperville where police point to Russian involvement--citing a suspect who got $18,000 in Zelle payments and fled the country to Moscow.
Here at home, when Slaton and Fogler told NBC 5 Responds they couldn't get their money or answers from their banks, we asked Chase and Bank of America why both claims were denied.
Neither bank answered that question, but--after our calls--did credit both accounts: a total of $5,300.
Zelle -- and the banks that use it--say the app should only be used with people you trust.
Slaton and Fogler say it's the bank and the app they don't trust.
The company that runs Zelle, Early Warning Services, says all financial products are susceptible to theft, it has seen "few" incidents compared it its overall volume and says any built-in delay would not provide additional protection. Something security experts we spoke to disagree with.