A 21-year-old gunman opened fire in a bank in the US state of Florida and killed five people before surrendering himself to a SWAT team, the police said.

The suspect called authorities to say he had opened fire in SunTrust Bank branch in Florida’s small city of Sebring on Wednesday. Authorities identified the suspect as Sebring resident Zephen Xaver, CNN reported.

Negotiations to try to get the barricaded suspect to leave the bank were not successful. What followed was a tense standoff with police negotiators that ended when an armoured police vehicle rammed into the bank doors, shattering their glass, according to a video footage.

The police said in a statement that the suspect eventually surrendered to the SWAT team at the bank. Video from the scene showed officers inching towards the broken glass with their firearms drawn. They soon emerged with the suspect in handcuffs.

“We’ve suffered significant loss at the hands of a senseless criminal doing a senseless crime,” said Sebring police chief Karl Hoglund.

The police said they were still investigating the motive for what the police chief called “coldblooded murder”. The man was charged with five counts of first-degree murder.

Zephen Xaver was employed as a correctional officer trainee at Avon Park Correctional Institution and resigned two weeks ago, according to Patrick Manderfield, a spokesperson for the Florida Department of Corrections.

The correctional institution is about 20 miles north of the bank where the shooting occurred.

SunTrust Chairman and CEO Bill Rogers said company officials “were deeply saddened by the tragic shooting” at the branch.