Agents with the Federal Bureau of Investigations (FBI) in the United States have fatally shot a man who was allegedly holding hostages inside a building in California.

The shooting ended an over 12-hour standoff at an office in Bakersfield that houses a bank branch and a school district office.

In a statement, the Bakersfield police said the suspect was killed in “an officer-involved shooting involving Federal Bureau of Investigation personnel”.

It added that “all hostages were located unharmed and received medical evaluation and treatment at the scene”.

Later, on Wednesday morning, the Bakersfield Police Department confirmed that 10 hostages had been involved in the standoff.

Jeremy Blakemore, the  assistant chief of the department, described them as employees of the Kern County Superintendent of Schools.

“We’re incredibly relieved to report that all of the hostages that were involved have been safely recovered and reunited with their families,” Blakemore said.

“There were a total of 10 members of our community whose lives were changed yesterday unexpectedly, but we are thankful that they have been reunited with their loved ones after this ordeal.”

Blakemore also offered a timeline for the standoff. Law enforcement had originally been called around 12:59pm Pacific time, following a bomb threat at the location. Police said the man barricaded himself inside with several people, two of whom were released Tuesday after negotiations with authorities.

Authorities established a wide perimeter around the building, evacuating the nearby City Hall and the police headquarters.

Bakersfield police sergeant, Eric Celedon, told reporters on Tuesday the department had “every single resource at our disposal out here to bring this to the safest resolution possible”.

Sid Patel, special agent in charge in the FBI’s Sacramento office, on Wednesday identified that attacker as 41-year-old Anthony Scott Searles-Harris.

Authorities did not release a motive, but said Searles-Harris had previously run-ins with law enforcement, including convictions in 2014 for sexual crimes related to a child under 14 years of age.

Records show he was released from prison in 2018.

Authorities also said that Searles-Harris had served about a year in the Army before being dishonorably discharged for going AWOL.