A coroner's inquiry into the case of a 73-year-old woman who died after a horse fell on her last year began yesterday with several questions posed to a police investigator which he was unable to answer.

Madam Lim Ah Boey was pinned under a 450kg horse for about 10 minutes at Gallop Stable's Punggol Ranch last Nov 14.

She had crush injuries and died in hospital shortly after.

The court heard from Staff Sergeant Tan Soon Kwang that Madam Lim had gone to the ranch with her family to celebrate her grandson's 21st birthday.

At about 5.30pm, she rode a horse for five minutes around a 264m track, led by a handler.

When it was time for her to dismount, however, the horse stopped short of a mounting block - a set of concrete steps. The handler led the horse to circle in front of the steps three times, in an anti-clockwise manner, but it did not go close enough to the steps each time.

On the fourth attempt, event manager Wan Jasma Zuraini Wan Jalani was seen to hit the horse's rear, and it seemed to get agitated.

Ms Jasma and the handler then tried to get Madam Lim to dismount without using the steps.

But Madam Lim's granddaughter saw that she was stiff and panicking, and shouted at her not to dismount as it seemed unsafe to do so.

The stable's staff then decided to walk the horse 20m away to a portable mounting block. But it suddenly reared, standing on its hind legs.

The second time it reared, Madam Lim fell. The horse then lost its balance and fell on top of her. It struggled to get up as it was stuck between the mounting block and a fence. After 10 minutes of failed attempts by the staff to get the horse on its feet, it got up on its own.

Madam Lim had a weak pulse and was still breathing, but her heart stopped beating shortly after. Her grandson, a combat medic, carried out cardio-pulmonary resuscitation while waiting for an ambulance. Madam Lim was pronounced dead at around 7pm.

An instructor later realised that the horse had not eaten , although it was supposed to have been fed between 12.30pm and 2pm. SSgt Tan said the the horse had also been working from 1pm to 6pm.

Madam Lim's family members sobbed as four clips of the incident - recorded by an unknown person, and posted online - were played.

The family was represented by lawyer Sunil Sudheesan, who asked SSgt Tan if he had seen the portable mounting block which the staff claimed they had wanted to use. He said he had not.

Among other questions he could not answer, the officer did not know the regulatory agency in charge of horses, or if handlers required any licensing. He was also unable to ascertain if the design of the mounting block was safe.

His report concluded there was no foul play involved in Madam Lim's death but he was unable to define foul play without prompting by the coroner. State Coroner Marvin Bay asked SSgt Tan, who has been a police investigator for 21/2 years, to prepare his answers by the next inquiry hearing, at a later date.