The British gunman who held four people captive at a Texas synagogue in a 10-hour stand-off that ended with the hostages escaping and an FBI tactical team rushing in was killed by multiple gunshot wounds, according to a medical examiner.

The Tarrant County Medical Examiner released initial information from the autopsy of Malik Faisal Akram on Friday, six days after the 44-year-old British citizen took hostages during morning services at Congregation Beth Israel in the Dallas-area suburb of Colleyville. The death was ruled as a homicide.

In Texas, a death being ruled a homicide indicates that one person was killed by another, but does not necessarily mean the killing was a crime.

Matt DeSarno, the FBI’s special agent in charge in Dallas, said at a news conference on Friday that Akram’s death “was a result of the deadly force used by the FBI”.

After taking hostages on Saturday, Akram could be heard on a Facebook livestream demanding the release of Aafia Siddiqui, a Pakistani neuroscientist who was convicted of trying to kill US troops in Afghanistan.

The prison where Siddiqui is serving her sentence is in nearby Fort Worth, but her attorney said Siddiqui said the prisoner had no connection to Akram.

Akram released a hostage shortly after 5pm but those remaining later said he became more belligerent and threatening as the night wore on. The stand-off ended around 9pm after Rabbi Charlie Cytron-Walker said he threw a chair at Akram and he and the two other remaining hostages fled.

Video of the stand-off’s end from Dallas TV station WFAA showed people running out a door of the synagogue, and then a man holding a gun opening the same door just seconds later before he turned around and closed it.

Moments later, several shots and then an explosion could be heard. The medical examiner determined that Akram died at 9:22pm.

Akram was from Blackburn. His family said he had been “suffering from mental health issues”.

He arrived in New York on a tourist visa about two weeks before the attack on the synagogue and cleared checks against law enforcement databases without raising any red flags, officials said. He spent time in Dallas-area homeless shelters before the attack.

The FBI is still investigating how Akram got the weapon, though it has had success in tracking his movements from the time he arrived in New York on December 29 until his entrance into the synagogue on January 15.

Mr DeSarno said the FBI was still reviewing his devices and scrutinizing his contacts. He was not known to the FBI or US intelligence communities until the hostage-taking.