A suspect entered a Bank of the West branch at 3931 S. Bristol Street at 11:30 a.m. Thursday and with a knife in his hand robbed a teller, then exited the bank with an undisclosed amount of money.
The suspect attempted to carjack three different vehicles unsuccessfully. He then allegedly robbed a victim of his bicycle and fled on the bike northbound on Bristol to MacArthur Boulevard.
A Good Samaritan driving by helped the bicycle-theft victim, giving a ride to the person as they chased the bank-robbery suspect. They located the suspect on MacArthur and Flower, confronted him and got into an altercation, according to Santa Ana Police.
Santa Ana police officers arrived and arrested the suspect.
The suspect was identified as 36-year-old Roberto Guillermo Dorantes. Dorantes was arrested for bank robbery, three counts of carjacking, four counts of assault with a deadly weapon, and one count of grand theft.
No one was injured in any of the incidents.
The FBI and Santa Ana Police were investigating Thursday's robbery.
Investigators believe the suspect was performing a copycat robbery similar to the method of the "$5K Bandit," an African-American male who has robbed another Santa Ana bank three times using a butcher knife.
Police are still seeking the "$5K Bandit." He is described as muscular African-American man with a dark complexion, between 30 to 40 years old, last seen wearing a gray long-sleeve shirt, dark or black pants, gloves, sunglasses and a black logo baseball cap with a broad red bill.
Anyone with information about the "$5K Bandit" should contact Los Alamitos Police Detective Jake Sorenson at (562) 431-2255, extension 407.
You can also contact Orange County Crime Stoppers at (855) TIP-OCCS or the FBI's Los Angeles office at (310) 477-6565.