Karam Umrani, a 28-year-old sub-inspector with the Islamabad police force, was close to Margala Towers when the building collapsed after the earthquake.
Karam Umrani was at the scene
He got in touch with the BBC News website and told how he rushed to the scene and began rescuing people trapped in the debris.
Margala Towers, 2330 (1830GMT)
I am back on the spot now.
But it has started raining here and that is hampering rescue operations.
There are still 30 to 40 people inside the debris, including the assistant commissioner of municipal government in Islamabad, who lived in Margala Towers.
He's alive and speaking from a mobile phone from inside the debris.
He says that he's in good condition and there are about 10 members of his family with him.
They've got enough air. We have provided them with oxygen and we arranged water and other necessities for them and, Inshallah, they will be saved.
Debris is being lifted by cranes and we are just continuing to talk to people.
I will stay here until further orders from above.
I am optimistic and I hope that within two or three hours everyone in the debris will come out.
Islamabad police dormitory, 1830 (1330GMT)
The cries of the people trapped in the debris haunt me. There are still many trapped there.
I was on duty at the time of the earthquake and close to Margala Towers when it struck.
I heard a blast. The ground shook violently and I saw only dust and mess everywhere. I was worried for my own life.
At Margala Towers, all I could see was rubble on the ground. I heard the cries of the people trapped inside there.
I could only do one thing which was to pick people out of the rubble and with my bare hands I started to dig.
First, I pulled out one dead body. A man whose head had been badly injured. I couldn't save him.
But then I managed to rescue somebody else.
I followed the cries and the voices from inside the rubble and I kept digging and following them till I found their source.
It was a man of 35. I carried him on my shoulders to the ambulance that was waiting. He had been inside the towers in an apartment. His head and legs were badly injured but at least he was alive.
I kept on hearing only shouts and voices.
Everyone was watching but we continued working, using what we had - our bare hands. I think I was in what was the basement of the building.
We stayed for one hour and by that time all the emergency agencies had arrived. Now, I am in the police dormitory taking a rest.
I thought about my family. I was very worried for them - they are in the Sindh province, I live alone in these dorms.
In about half-an-hour I have to go back to Margala to continue the rescue effort.