(Updates with testimony of police on why they failed to stop attack.)

By Hamid Shalizi

KABUL, May 3 (Reuters) - Video of a crowd killing an Afghan woman accused of burning pages from a Koran was shown in court on Sunday in the trial of nearly 50 people over a lynching that prompted outrage and protests in Kabul.

The judge asked prosecutors on the second day of the trial to play footage, shot with mobile phone cameras, of a crowd kicking and beating the 27-year-old woman, named Farkhunda.

A total of 49 men, including several police officers, are on trial in the killing.

Some police are accused of standing by and allowing the crowd to kill the woman in broad daylight and setting her body on fire. An investigation later showed she had been falsely accused.

Sunday's testimony focused on whether police incompetence contributed to the failure to save Farkhunda.

"We were informed about the incident when it was too late. I dispatched a team there immediately, but unfortunately we could not save her," Kabul Police Chief Abdul Rahman Rahimi told the court.

However, the police mobile response team that was called to the scene by dispatchers did not immediately respond.

A team member named Frotan testified that he was with his sick mother at a hospital when the dispatch came through and he had left his radio in the car with his children.

His children were playing with the radio when he returned and he never realised he had been called to the scene, said Frotan, who like many Afghans uses just one name.

The attack has proved a polarising incident in Afghanistan, a deeply conservative Muslim country.

Some say the killing was a defence of Islam. Many others were outraged at the viciousness of the attack, even before an investigation showed that Farkhunda had been falsely accused of desecrating Islam's holy book.

Several protests against violence against women sprang up in Kabul, including one in the past week that re-enacted the attack.

It was unclear when a verdict would be handed down in the trial, which was originally expected to last two days.

(Writing by Kay Johnson; Editing by Paul Tait)