What is this sound?

I was sleeping at night, when I suddenly heard some bashing sound from downstairs.My parents were out of the town as my grandfather suddenly felt sick.

Hi! we are from USA.

Before this incident two foreigners, who were said to be  my uncle's friend came to live in our house for a week. For the first five days they lived splendidly with us.

And on the sixth day this incident happened.

When I heard the noise first I ignored it but it grew louder . I was uptight but somehow I decided to check what was happening .When I went out of my room I saw my elder brother Mohit standing on the stairs and trying to hear something.

I asked my brother and he told me that the two foreigners were arguing and he had heard their conversation. Actually the two foreigners were wicked people  and they were planning to steal my mother's precious  jewellery sets kept in the chest, they somehow managed to make the duplicate key but that key was not fitting in the keyhole.

AAAAHH! Help we are

having a stomach ache

Now my brother and I knew their plan so we had to stop them from stealing the jewellery. Without  wasting time we came back to room and started calling police and our father. Unfortunately the weather was very bad and cloudy outside so there was no signal . Then, we decided to do acting of stomachache and luckily that plan worked. We have managed to keep them busy with us in our room that night.

Next day in the early morning we went in their room and searched for the duplicate key. When I stood on the stool I saw the key lying above the cupboard. We took that key and went to our parents room.

We were astonished because the chest opened at the first try only. Though we understood that the foreigners were trying to put the key in a wrong position .We felt very hilarious that time, we sticked some pieces of paper in the keyhole so that the chest cannot get open .