Sheriff's deputies stopped a large group of vehicles in the northbound lanes of Interstate 110 in Hawthorne, south of Los Angeles, and searched some vehicles before taking several men from a black car into custody.
The freeway was briefly closed south of the search area and reopened shortly after 1 p.m., said Sgt. Denise Joslin, a California Highway Patrol spokeswoman.
The search came after three armed men robbed a credit union in Moreno Valley, in neighboring Riverside County, at 9:20 a.m. and fled, said Sgt. Lisa McConnell, a Riverside County sheriff's spokeswoman.
A signal revealed that the tracking device was in roughly the same area as the freeway closure, she said, declining to confirm the men seen being taken into custody on live TV were the bank robbery suspects.
Los Angeles County sheriff's spokeswoman Deputy Lillian Peck referred questions to Riverside County officials and said two Los Angeles County sheriff's stations were assisting with the search.
Joslin, with the CHP, estimated that traffic was backed up at least a mile during the search.
At one point, cars entering the freeway began to back up on an on-ramp to avoid getting trapped in the traffic jam.
It's not uncommon for banks to slip tracking devices in with stolen money to help police, but it's a practice that banks and law enforcement prefer to keep quiet, McConnell said.
Earlier this year, for example, a man was captured in Des Moines, Iowa, after a teller at a credit union slipped a GPS device into a bag along with nearly $6,000 in cash.
In February, a serial bank robber suspected of hitting locations in five states was arrested in Kentucky after a teller at one bank was able to slip a tracking device in with the money.
And in Illinois, a man was caught 30 minutes after making off with more than $7,000 because of a tracker, according to news reports.
