Olson (right) was already facing separate charges
The five, who include guerrilla-turned-housewife Sara Jane Olson, are being held in the Californian city of Sacramento.
The other suspects are ex-husband and wife Emily and Bill Harris, Olson's brother-in-law Mike Bortin, and James Kilgore. All except Mr Kilgore, who has been on the run since the robbery, are due to appear in court on Friday.
Sacramento District Attorney Jan Scully said the new evidence against the five included a forensic match of the lead pellets that killed Opsahl with shotgun shells found at an SLA hideout in San Francisco.
"We all agree that after almost 27 years, justice has not been served," Mr Scully told a news conference.
Opsahl's doctor son Jon said he was delighted that charges had finally been brought.
The SLA abducted Patty Hearst in 1974.
Hearst was waiting in the getaway car during the robbery. She joined the SLA, changing her name to Tania, after being held captive in a cupboard for two months.
Hearst was granted immunity from prosecution for the bank robbery murder in the 1970s.
She co-operated with police and claimed in her 1980s autobiography that all five suspects were at the scene of the murder.
Hearst herself was convicted of involvement in another bank robbery, but was freed by then President Jimmy Carter after serving 23 months of a seven-year jail term.
She was pardoned last year by outgoing President Bill Clinton.
'Soccer mom'
Olson, 54, formerly Kathleen Soliah, is due to be sentenced in Los Angeles on Friday after admitting two counts of attempting to murder policemen by blowing them up with pipe bombs.
After nearly 25 years on the run, Olson was found in 1999 living quietly in Minnesota as a suburban "soccer mom".
She is facing a sentence of 10 years to life in prison on each count.