The police watchdog has passed a file of evidence to prosecutors to decide whether a Metropolitan Police officer should be charged over the fatal shooting of an unarmed black man.

Chris Kaba, 24, who had been due to become a father, died after he was hit by a single gunshot fired by an armed officer on September 5 last year in Streatham Hill, south London.

The Independent Office for Police Conduct (IOPC) said on Thursday it had referred a file of evidence to the Crown Prosecution Service (CPS) following the conclusion of a homicide investigation.

Mr Kaba’s family welcomed the move and urged the CPS to prosecute the officer, who has been suspended from duty while under investigation for murder.

We will now carefully consider the file of evidence to determine whether criminal charges should be brought in relation to the fatal shooting of Chris Kaba

In a statement issued through the charity Inquest, the family said: “This step forward is necessary and welcome. We urge the Crown Prosecution Service to do their bit and provide their advice to the IOPC urgently.

“We very much hope that the CPS advise in favour of a prosecution and that the truth will emerge, without delay, through criminal proceedings. Our family and community cannot continue waiting for answers.”

IOPC director Amanda Rowe said investigators had been working hard to complete the probe within the six-to-nine-month deadline.

She said: “During the investigation, the officer was advised they were under criminal investigation for murder and following the conclusion of our investigation we have referred a file of evidence to the CPS to determine whether to charge the officer.

“A referral to the CPS does not necessarily mean that criminal charges will follow. It is now for the CPS to decide, applying the tests in the Code for Crown Prosecutors, whether or not to prosecute the officer.”

An inquest opening in October heard Mr Kaba was blocked by a marked police vehicle while driving an Audi and there was “contact” between the two cars before a marksman fired a single shot through the windscreen, hitting him in the head.

Nick Price, head of the CPS Special Crime and Counter Terrorism Division, said: “We will now carefully consider the file of evidence to determine whether criminal charges should be brought in relation to the fatal shooting of Chris Kaba.

“As always, we will make that decision independently, based on the evidence and in line with our legal test.”