Image caption Ahmad Shah was gunned down in April last year

A special Afghan tribunal has convicted three men of being involved in the murder of BBC journalist Ahmad Shah, a spokesman for the attorney general's office has told the BBC.

Mr Shah, who worked for the BBC's Pashto language service, was shot dead by unidentified gunmen last April.

The special anti-terrorism tribunal sentenced one man to death, the second one to 30 years in prison, and the third one to six years in prison.

The case is going to the appeals court.

The identity of Mr Shah's murderers have not been made public and their motive is not clear.

The attorney general's office said the three were detained in Parwan prison (also known as Bagram jail), which mostly houses prisoners accused of terrorism, and the trial was held there.

Ahmad Shah joined the BBC from local radio in early 2017 with a brief to cover his home province of Khost, in south-eastern Afghanistan, but he branched out to cover the neighbouring provinces of Paktia and Paktika as well for television, radio and online.

He first started working for the BBC as a freelance contributor before being recruited as a full-time reporter by BBC Pashto.

He was killed as he cycled home to the village where he lived outside Khost city, and died of his injuries in hospital.

Local security officials say the attack was carried out by two gunmen riding a motorbike.

Mr Shah had not received any work-related threat or threatening calls, and his family was involved in no feuds, according to his father.

The Taliban denied any involvement in his killing, saying "he was a professional journalist and we are saddened" by his death.

Image caption It remains unclear why Mr Shah was killed

He was the fifth BBC staff member to have been killed in Afghanistan since the country's devastating civil war in the 1990s. The others were:

Mirwais Jalil , 25, who was attacked by four gunmen in 1994

, 25, who was attacked by four gunmen in 1994 Abdul Samad Rohani who was shot dead in Helmand Province in 2008

who was shot dead in Helmand Province in 2008 Ahmed Omed Khpulwak , 25, who was mistakenly killed by Nato-led forces in 2011

, 25, who was mistakenly killed by Nato-led forces in 2011 Mohammed Nazir, a BBC driver who was killed in a bomb attack in 2017

Dozens of private radio stations and TV channels, as well as hundreds of publications, have been launched in Afghanistan in recent years.

But the country remains one of the most dangerous places for journalists in the world.

The day Ahmad Shah was shot dead, 30 April, was the deadliest for the media in the country's history.

Nine members of the press had been killed earlier in the day as they gathered to cover a suicide attack in Kabul.